Evolution, Medicine, and Public Health Advance Access published February 28, 2016
Address for correspondence:
Prof. Dr Martin Brüne, LWL University Hospital, Department of Psychiatry, Psychotherapy and Preventive Medicine, Division of Cognitive Neuropsychiatry and Psychiatric Preventive Medicine, Ruhr-University Bochum, Alexandrinenstr. 1, D-44791 Bochum, Germany.
Phone: +49-234-5077-1130, fax: +49-234-5077-1329, e-mail: firstname.lastname@example.org
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© The Author(s) 2016. Published by Oxford University Press on behalf of the Foundation for Evolution, Medicine, and Public Health. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted reuse, distribution, and reproduction in any medium, provided the original work is properly cited.
The term “Borderline Personality Disorder” (BPD) refers to a psychiatric syndrome that is characterized by emotion dysregulation, impulsivity, risk-taking behavior, irritability, feelings of emptiness, self-injury and fear of abandonment, as well as unstable interpersonal relationships. BPD is not only common in psychiatric populations, but also more prevalent in the general community than previously thought, and thus represents an important public health issue.
In contrast to most psychiatric disorders, some symptoms associated with BPD may improve over time, even without therapy, though impaired social functioning and interpersonal disturbances in close relationships often persist. Another counterintuitive and insufficiently resolved question is why depressive symptoms and risk-taking behaviors can occur simultaneously in the same individual. Moreover, there is an ongoing debate about the nosological position of BPD, which impacts on research regarding sex differences in clinical presentation and patterns of comorbidity.
In this review, it is argued that many features of BPD may be conceptualized within an evolutionary framework, namely behavioral ecology. According to life history theory, BPD reflects a pathological extreme or distortion of a behavioral “strategy” which unconsciously aims at immediate exploitation of resources, both interpersonal and material, based on predictions shaped by early developmental experiences. Such a view is consistent with standard medical conceptualizations of BPD, but goes beyond classic “deficit”-oriented models, which may have profound implications for therapeutic approaches.
The term Borderline Personality Disorder (BPD) refers to a psychiatric condition that is characterized by unstable interpersonal relationships, fear of abandonment, difficulties in emotion regulation, feelings of emptiness, chronic dysphoria or depression, as well as impulsivity and heightened risk-taking behaviors. Paranoid ideation and dissociative states are also transient features of the syndrome (Table 1). Moreover, many patients with BPD show recurring self-injurious or suicidal behavior . BPD has a lifetime prevalence of about 6 percent. It is much more common in clinical settings, thus rendering BPD highly relevant for health care providers and public health in general .
Table 1. Descriptive diagnostic criteria of Borderline Personality Disorder according to the Diagnostic and Statistical Manual of Mental Disorders, fifth edition (DSM-5). A diagnosis is based on the presence of at least 5 of the following signs or symptoms:
Etiological models of BPD suggest that the development of “mistrustful inner working models” based on insecure attachment predisposes to perceiving others as untrustworthy and rejecting [3-5]. Causal factors in this development include childhood trauma such as emotional neglect or physical and sexual abuse, though associating BPD with traumatic events alone is an oversimplification [6-8]. The contribution of genetics to BPD is inconclusive, but heritability of BPD seems to be significant [9, 10]. Taken together, the experience of early adversity, particularly the emotional unresponsiveness of attachment figures, trauma or abuse, coins an individual’s expectations with regard to future resource availability, including the quality of interpersonal relationships in terms of others’ reliability and trustworthiness .
BPD is often a comorbid condition of other psychiatric disorders (formerly conceptualized as axis-I disorders according to DSM-IV), foremost depression, other personality disorders, and there seems to be syndromal overlap and/or comorbidity with bipolar disorder, attention deficit/hyperactivity disorder (ADHD) and posttraumatic stress disorder (PTSD) [2, 11-14].
In keeping with traditional medical conceptualizations, many scholars see BPD as a clinical syndrome with identifiable brain lesions or defects, mainly affecting fronto- limbic connections, which account for patients’ emotional dysregulation, impulsivity and inability to cope with interpersonal distress [e.g., 15]. Such views are incompatible, however, with observations suggesting that interpersonal difficulties of individuals with BPD are largely absent outside emotionally challenging situations, and that over time many patients experience a substantial reduction in self-mutilating behavior and impulsivity, though full recovery is rare and interpersonal difficulties and emotional instability are more pervasive . In fact, most psychiatric conditions worsen with increasing age, so, why should BPD be an exception? Another counter- intuitive issue pertaining to BPD is that risk-taking behavior and depression co-occur in the same condition, whereby people with depression are usually risk-averse, rather than risk-prone, the latter being a typical feature of BPD . Finally, there is controversy about sex differences in prevalence and clinical presentation of BPD, much of which remains unresolved, possibly due to conceptual diversity [18-20].
In consideration of these conceptual inconsistencies, the present article seeks to shed a different light on BPD. It is proposed that some features of BPD can be better understood in a frame of reference taking into account insights from behavioral ecology. Accordingly, cognition, emotions and behaviors typical of BPD may become meaningful and comprehensive, sometimes even logical, when imagining a world that is dangerous and unpredictable, where a “fast and furious” lifestyle may appear appropriate. Such a view does not contend that BPD is adaptive per se.
Instead, it is suggested that individual signs and symptoms associated with BPD can be meaningfully integrated in a life history perspective, and that sub-threshold or “diluted” phenotypes of BPD may well pay off reproductively (i.e. being adaptive in the biological sense), though perhaps at the expense of well-being and mental health. With regard to clinical implications, it is claimed that a behavioral ecological perspective may also shift focus in relation to psychotherapeutic goals away from fighting signs and symptoms (i.e. “dis-ease”) to views that aim at reframing an individual’s life history strategy in more functional ways by means of improving patients’ insight into and acceptance of the inter-relatedness of early life experiences with the pursuit of current bio-social goals.
Behavioral Ecology focuses on the variation in behavior between as well as within species and its contingency on environmental conditions. An important behavioral ecological concept, termed Life History Theory (LHT), concerns an organism’s differential allocation of resources to physical growth and reproduction. Put another way, there is a trade-off between an organism’s capacity to invest energy in somatic growth, as opposed to investment of energy in reproductive activity, resulting in different Life History strategies (LHS) shaped by natural selection. Accordingly, growth rate, age and body size at sexual maturation, number and size of offspring, mortality rate, longevity etc. are biological traits modeled by environmental contingencies .
The concept of LHT was originally applied to differences between species, with growing evidence for within-species differences in LHS . That is, ecological (environmental) conditions (interacting with genetic factors) determine whether an individual adopts a “faster” or “slower” LHS, whereby current and future resource availability is estimated by observable cues or predicted based on prior experience acquired in early developmental stages .
Critical aspects involved in “decisions” over faster or slower LHS concern the timing of biological maturation, current versus future reproduction, quality versus quantity of offspring, and quality versus quantity of parental care in offspring and mating [24, 25].
A wealth of research has shown that the principles of LHT apply to humans in the same way as to any other organism . It is necessary to point out, however, that terms such as “strategy” or “decision-making” do not imply conscious reflection or intentional action. The timing of biological maturation, sexual activity and intensity of care for offspring is regulated by sex hormones, the stress response system, and neuropeptides [26-28]. In a more general vein, however, LHS have also profound ramifications for the shaping of interpersonal behavior including cooperation, reciprocity, aggression, and pair-bonding, as well as for neurocognitive domains such as risk-taking, executive functioning, and inhibitory control . According to the “Adaptive Calibration Model” individual differences in stress- regulation, as a function of complex gene-environment interaction, may translate into different adaptive strategies, which may shift one’s somatic development and psychological mechanisms towards a “faster” or “slower” LHS [25, 27].
In support of theories about LHS, abundant research suggests that differences in early environmental conditions shape an individual’s LHS in predictable ways . Central to this is the observation that the quality of parenting profoundly influences the way children develop “inner working models” which in turn serve as a guideline for predicting future resource availability . That is, children who grow up in an emotionally safe and stable familial environment learn to see the world as a safe place, in which stable relationships with trustworthy others (family, peers, partners) indicate the availability of social and material resources in the future. Accordingly, from the perspective of attachment theory, securely attached individuals tend to pursue slower LHS, that is, they tend to mature later, delay reproduction, are generally risk averse, and form stable long-term intimate relationships with partners. Such individuals are also cooperative, empathetic, display low levels of interpersonal aggression, and have good inhibitory control over impulses. In terms of personality traits, they score high on conscientiousness and agreeableness. In contrast, children who are exposed to environmental cues such as harsh parenting, violence or other sources of danger are more likely to develop an inner working model suggesting that future resource availability is unpredictable, thereby shifting LHS towards faster development, including earlier biological maturation, sexual activity and earlier reproduction [24, 29]. A faster LHS is more often associated with insecure attachment patterns, increased delay discounting, greater impulsivity, larger numbers of sexual partners, lack of reciprocity, reduced inhibitory control, increased risk-taking behavior, and less parental effort. Moreover, several personality traits may also be linked to differential LHS, whereby conscientiousness and agreeableness may be the most relevant in this regard, whereas others such as extraversion, openness and neuroticism may be more ambiguous indicators of a particular LHS (Table 2) [30, 31].
Table 2. Prediction from Life History Theory with regard to cognitive, emotional development, interpersonal behavior and physiology (modified after Del Giudice, 2014). Supportive evidence for Borderline Personality Disorder as a “fast” Life History Strategy (LHS) is indicated by asterisks. Superscript numbers refer to references cited in the text.
In line with LHT models of socialization, and consistent with the Adaptive Calibration Model, the experience of early adversity, particularly emotional unresponsiveness of attachment figures, trauma, abuse, coin an individual’s expectations with regard to future resource availability in terms of interpersonal relationships, i.e. trustworthiness, reciprocity and empathetic concern, suggesting that individuals would tend to maximize short-term benefits from interpersonal relationships, that is, pursue a fast LHS [27, 29, 32].
Accordingly, the idea that BPD is typical of a “fast” LHS has face value, because several diagnostic criteria such heightened impulsivity, emotional dysregulation, and risk-taking behavior already point in that direction, as well as the prevalence of adverse experiences during childhood. In extension to this, LHT would predict that people with BPD may show signs of high stress responsivity (which may be a distinguishing feature from antisocial personality traits or disorder, where a more unemotional reactivity pattern is typical), a lack of trusting relationships, unstable romantic relationships, high number of short-term sexual relationships as well as increased vigilance towards partners’ faithfulness, early biological maturation, and poor investment in own offspring . Moreover, symptom patterns were expected to differ between men and women, with male patients showing more externalizing features and females showing more internalizing behaviors . Furthermore, comorbid conditions of BPD should feature among those syndromes associated with a “faster” LHS, including attention deficit/ hyperactivity disorder (ADHD), perhaps except the inattentive type of ADHD, bipolar disorder (BD), substance abuse, and bulimia nervosa (BN) .
Traits associated with BPD following a fast LH strategy
One key feature of BPD concerns patients’ difficulties in regulating their emotions in appropriate ways, which may account for several symptoms including idealization and derogation of others, impulsivity and risk-taking behavior. These signs and symptoms can be conceptualized as behavioral expression of high stress responsivity. According to the Adaptive Calibration Model high stress responsivity promotes a fast LHS in dangerous and unpredictable contexts, whereby it increases vigilance to threat and down-regulates one’s sensitivity to social feedback [27, 34]. Consistent with this hypothesis, several studies have shown alterations of the hypothalamic-pituitary-adrenal (HPA) stress axis in BPD, which correlate with symptom severity and a history of childhood trauma . In fact, early adversity in general has been found to be associated with persistent changes of stress responsivity, possibly via epigenetic mechanisms . Along similar lines, research into emotion perception suggests that patients with BPD display heightened vigilance or avoidance reactions to negative emotions such as fear and anger [37, 38]. At the same time, patients with BPD are often “alexithymic”, that is, they have difficulties in reflecting upon own and others’ emotions, whereby alexithymia in BPD has been found to be related to stress intolerance and impulsivity . This apparent “empathy paradox” however, is plausible considering LHS emerging from early adversity . Linehan has argued that patients with BPD may be hyper-sensitive to emotional cues that potentially signal rejection or abandonment . Such biased emotion perception impacts on social interaction, if it interacts with difficulties in emotion regulation arising from over-activation of the attachment system . Overactivation of the attachment system leads to a functional down-regulation of mentalizing abilities, partly, as a means of self-protection against continuing traumatization by an abusive caregiver . Accordingly, hypersensitivity towards negative emotions may further contribute to distorted views of others, such that others are generally perceived as untrustworthy [42, 43]. In turn, seeing others as untrustworthy and uncooperative may enhance one’s own (unconscious) opportunistic attitude towards short-term exploitation of resources .
This view is also compatible with research showing enhanced impulsivity and delay discounting in patients with BPD. In fact, if one’s inner working model suggests poor resource availability in the future (compatible with a fast LHS), immediate resource acquisition is a logical consequence. In line with predictions, empirical evidence suggests that patients with BPD are poor in impulse control and in tolerating delay of gratification, that is, they prefer immediate (lower) gains over (higher) future monetary gratification .
Personality traits and interpersonal behavior
Research involving theories of temperament and personality development suggests that a fast LHS would be associated with high scores on novelty seeking, low scores on cooperativeness and harm avoidance, and low scores on agreeableness and conscientiousness, whereby high scores on the latter two dimensions were more characteristic of slow LHS [25, 31, 46]. In addition, the exploitation of others is typical of Machiavellian personality traits .
Consistent with this hypothesis, one study reported higher scores on novelty seeking and lower scores on cooperativeness in BPD patients compared to nonclinical and clinical controls . In another study, BPD patient scored higher on Machiavellianism than controls . These findings are consistent with the hypothesis of a fast LHS in BPD. Our own research group has utilized neuroeconomic games and responsivity of patients to the intranasal administration of a single dose of oxytocin to study LH-relevant behavior in BPD. For example, in a study using a Dictator Game version, in which participants had the option to punish observed unfairness occurring during an interaction of two characters, we found differences in personality traits between BPD patients and controls, which had diametrically opposite impact on participant’s motivation to engage in third-party punishment. In line with predictions regarding the association of personality traits with a fast LHS, patients with BPD scored higher than controls on Machiavellianism, and lower on agreeableness and conscientiousness. Most interestingly, in BPD third-party punishment correlated Machiavellianism (and with neuroticism), and inversely with agreeableness (as a measure of empathetic concern for others), which was the reverse in nonclinical controls. This finding is consistent with the interpretation that patients with BPD seemed to pathologically identify with the disadvantaged person in the Dictator Game, whereby antisocial traits motivated patients to punish unfair behavior, rather than empathic concern for others .
In a similar vein, research into interpersonal trust and cooperation has revealed that individuals with BPD have difficulties in maintaining and re-establishing reciprocal trusting relationships. For example, King-Casas et al. used a so-called trust game (TG), where one player (the investor) is endowed with a sum of money units (MU), of which he or she can “invest” a proportion of his choice in another player (the trustee) . The trustee then decides how much he or she is willing to return to the investor (as a measure of reciprocality and cooperation). Mistrustful investors are less likely to spend a substantial share, because they would expect an insignificant return by the trustee. Conversely, mistrustful trustees unlikely reciprocate, if the TG is played iteratively with the same investor, because they probably expect the investor to defect over time. BPD patients, as trustees, initially returned as many MUs as controls. However, contrary to controls, patients’ willingness to reciprocate diminished over successive rounds. Moreover, when the investor’s behavior was experimentally manipulated such that the trustee was frustrated by the lack of the other player’s cooperation, psychologically healthy subjects could be coaxed back into cooperation by overly generous investments, whereas BPD patients did not respond to cajoling . In further support of a fast LHS associated with BPD, Unoka et al. found that BPD subjects, in the role of an investor in a TG, transferred fewer MUs than patients with depression and healthy controls, depending on symptom severity such as stress-related paranoia and difficulties in interpersonal relations, as well as with a lack of confidence in the trustee (i.e. reduced trust) . Likewise, another study reported that patients with BPD, as investors, adjusted their investment in that they transferred fewer MU to unfair trustees while ignoring – unlike nonclinical controls – the trustee’s neutral or negative facial expression . These findings are therefore compatible with the view that BPD patients act in quite opportunistic ways and disregard emotional signals of others that might guide one’s decision of whether or not to cooperate with others.
Another feature, often considered pathognomonic for BPD, is self-injurious behavior. Self- harm may occur in BPD in situations in which patients feel detached from their social environment or have activated their attachment system in the fear of being abandoned. While self-injury can be seen as the expression of the inability to differentiate inner experience from reality, an evolutionary view suggests that self-harm can also be a strong signal addressed at perceived attachment figures, including therapists . In humans, parental care for offspring is extremely expanded, such that a threat posed by offspring to terminate one’s life is a menace to the biological fitness of the parents themselves. Put another way, self-imposed threat to the physical existence by offspring is perhaps the strongest signal on the side of the offspring to increase parental care and nurturance, and this may well be transferred to therapeutic relationships .
Sexuality and mating
According to Del Giudice et al.’s Adaptive Calibration Model, a fast LHS would predictably be associated with increased risk-taking, earlier sexual intercourse, and larger numbers of sexual partners. In addition, biological maturation is expected to be accelerated [24, 27, 29]. Indeed, a large population-based study revealed that early age at first sexual intercourse predicted lifetime number of sexual partners and future risk-taking behavior in general . With regard to BPD, several studies have found that women with BPD engage earlier in sexual intercourse and have more sexual partners than non-borderline women [33, 56, 57]. In addition, BPD women experience more often partner violence, date rape and sexual coercion . Moreover, comorbid substance abuse puts BPD subjects at risk for unprotected casual sex, sexually transmitted diseases and commercial sex work [58, 59]. Symptom severity of BPD is furthermore associated with teenage pregnancy, unplanned pregnancies and live births, but not number of abortions . According to a recent survey in over 100 in-patients with BPD, a majority reported significantly more sexual partners in the past 12 months than healthy controls, BPD subjects also expected to have more sexual partners in the near future than controls, and they reported a greater willingness to engage in risky health behaviors, but not financial risks (Brüne et al., unpublished material). In further support of the idea that BPD reflects a fast LHS, individuals with BPD are more likely to experience breakups of relationships , even though individuals with borderline features engage more in costly mate retention tactics, whereby monopolization of time, emotional manipulation, commitment manipulation, violence against rivals, submission and debasement, and verbal possession signals are more frequently observed in men, whereas jealousy induction, derogation of competitors, and derogation of the mate is more prevalent in women . This is compatible with a fast LHS, because these mate retention tactics are more likely to work effectively in the short term, but less so in the long run. This may be so, because they are costly to the pursuer, and aversive to one’s mate, which may, in fact, increase the likelihood of a breakup .
In contrast to the idea that BPD reflects a fast LHS, there is no evidence so far for an earlier somatic maturation such as age at menarche in BPD [33, 57]. This poses a serious drawback on the theoretical conceptualization of BPD as a pathological variation of a fast LHS. Research in nonclinical youths suggests, however, that younger age at menarche in girls is associated with increased risk for psychopathology [64, 65]. For example, early maturing girls exhibit higher levels of internalizing stress and aggression, particularly those who have experienced emotional numbing in response to peer stress . Precocious menarche also seems to non-genetically impact on the development of conduct disorder in girls . Taken together, these studies suggest that earlier sexual maturation in girls is associated with sub- threshold BPD or at least with important “core” features of BPD.
A fast LHS would not only be compatible with high mating effort, it would also be associated with low parental effort. In fact, invalidating parenting may be one mechanism involved in the transgenerational transmission of BPD personality traits . In line with the hypothesis of a fast LHS in BPD, mothers with BPD seem to display critical and intrusive behaviors, as well as role confusion (i.e. fear of being abandoned by own offspring) and frightened or frightening behaviors. This oscillation between over-involvement and withdrawal as well as between hostility and coldness seems to be characteristic of mothers with BPD . Our own observation in an in-patient sample of patient with BPD seems to corroborate this conclusion. We found that a relatively large number of patients with BPD came from a family background in which the biological father was absent, or multiple consecutive stepfathers had been present during childhood and adolescence of the affected individual. Moreover, several patients have half-siblings from relationships of their mothers with multiple partners.
Likewise, we observed among in-patients with BPD that a substantial number of women have been forced to give their children into foster care or under the auspices of youth welfare services (Brüne, Edel, and co-workers, unpublished data), which, from an evolutionary perspective makes sense in light of the assumption of a fast LHS.
Are there features of BPD following a slow LHS?
Even though the overall pattern of behavior in BPD, as well as the underlying cognitive and emotional processes, implies a fast LHS, some traits associated with the syndrome are rather suggestive of a slow LHS. These could, in part, reflect compensatory mechanisms for behaviors at the fast end of the continuum. In fact, BPD is not a stable condition, and it could well be that “slowing” (rather than “slow”) features emerge secondary to negative experiences following the pursuit of a fast LHS. As Del Giudice points out, while risky strategies may yield large gains in case of success, they also impose considerable costs in case of failure. For example, a defensive strategy in BPD could serve the purpose to avoid abandonment, which could explain why BPD patients score high on “harm avoidance” [25, 46, 48]. However, as shown above, this does not seem to apply to sexual harm [55-60].
Another feature, typically found in individuals with BPD, is the tendency of patients to denigrate themselves, which may be expressed by feelings of emptiness or self-disgust. In fact, disgust seems to be a relevant factor involved in patients’ self-concepts, whereby the degree of disgust is often linked to the severity of traumatizing experiences . High sensitivity to disgust interferes with a fast LHS, particularly in relation to sexual behavior. Conversely, insensitivity to disgust may bare the risk of contracting sexually transmitted diseases . Following this line of reasoning, the presence of disgust could be an indicator of a slowing LHS, even though it seems relevant to distinguish between pathogen, moral and sexual disgust, whereby the latter two correlate with conscientiousness and agreeableness in nonclinical subjects, which is implausible in the case of BPD, because conscientiousness and agreeableness are usually low in BPD .
Abundant evidence suggests that childhood maltreatment is associated with reductions in volume of limbic areas and the corpus callosum, and that impulsivity in BPD is associated with alterations in blood flow in frontal cortical regions [71-74]. While this review cannot summarize all relevant neuroimaging findings in BPD, an important issue with regard to the interpretation of neuroimaging data concerns the view suggesting that alterations in brain metabolism or structure do not necessarily reflect defective functioning. According to Teicher et al., early environmental stress, e.g., in the form of childhood neglect or abuse, is possibly not simply toxic to the brain, thus interfering with (normal) brain development . Instead, “exposure to significant stressors during a sensitive developmental period causes the brain to develop along a stress-responsive pathway”, thereby eliciting “a cascade of stress responses that organizes the brain to develop along a specific pathway selected to facilitate reproductive success and survival in a world of deprivation and strife” . This fundamentally different view of structural and functional brain imaging findings is in full accordance with the Adaptive Calibration Model according to which early experiences not only shape the psychological development of inner working models and how individuals adapt their LHS according to their predictions of future resource availability, but also that early experiences leave a mark on how the hardware (i.e. the brain) supports the operation of one’s individual software (i.e. inner working model) . In the case of BPD, this suggests that alterations in limbic structure may actually support a fast LHS.
A recent review concluded that despite evidence for heritability of around 40% of BPD, the search for candidate genes involved in BPD has been disappointing, which could relate to the “tendency to look for genetic effects on disease rather than genetic effects on vulnerability to environmental causes of disease” . Generally speaking, research into psychiatric genetics has largely focused on the diathesis-stress model, according to which subjects are vulnerable to develop a disorder if carrying a genetic variant that meets some sort of adversity or negative life event . Conversely, some genetic variation may protect against the development of a disorder even in the presence of severe adversity . The diathesis stress model can, however, not explain why so many “vulnerability genes” have undergone recent positive selection in human evolution. This is contradictory in itself, because it is implausible to assume that natural selection has favored allelic variants, which increase vulnerability to adversity . Instead, this strongly suggests that these genes exert hitherto undetected or overlooked beneficial effects with regard to reproductive fitness (which is not necessarily the same as “good for health”) . Accordingly it has been argued that a particular genetic variation that predisposes to pathology if associated with early adversity can have beneficial effects when environmental contingencies are developmentally more supportive [78, 79]. This suggests that it is more accurate to speak of differential susceptibility or plasticity conferred by genetic variation – i.e. responsivity to both positive and negative conditions – rather than focusing one-sidedly on vulnerability, whereby plasticity genes can have additive effects, that is, the susceptibility to the environment may increase with the number of plasticity alleles [80, 81]. It is therefore plausible to assume that the same genetic polymorphism can be linked to a “faster” or “slower” LHS, depending on the quality of early environments.
A look into genes involved in oxytocin (OT) turnover may exemplify this view. Genes coding for the oxytocin receptor (OXTR), genes coding for OT and genes that indirectly contribute to OT expression such as CD38 have been linked to social cognition and interaction including quality of marital relationships, as well as childhood problems, which renders them interesting candidates for research in BPD [82-85]. Moreover, imaging genetic studies suggest that polymorphic variation of the oxytocin receptor gene (OXTR) is associated with structural and functional differences in limbic structures, which are known to contribute to emotion regulation, a key dysfunction in BPD .
Indirect evidence from studies in non-clinical samples linking the OXTR with childhood adversity, insecure attachment and emotion dysregulation indicate that the OXTR may also play a role in BPD or subthreshold phenotypes. From a LHT perspective, one would expect that one allele would convey plasticity, whereby the association with early adversity would more likely lead to a fast LHS, and association with supportive environments would produce a slow LHS. The phenotype associated with the other allele would be unresponsive to environmental influence. In partial support of this idea, gene-environment interaction between childhood maltreatment and both emotional dysregulation and attachment style that was moderated by polymorphic variation of the OXTR gene, whereby homozygous G-carriers of the single nucleotid polymorphism (SNP) rs53576 showed more pronounced emotional dysregulation and disorganized attachment patterns when exposed to childhood trauma compared to A/G or A/A allele carriers . In contrast, parental emotional warmth and family stability compensated, in part, for the effects of traumatic experiences on mood and resilience in carriers of at least one G allele . Along similar lines, individuals who experienced childhood maltreatment were susceptible to developing depression when carrying at least one G allele, whereas A/A carriers were less responsive to early adversity .
Conversely, a recent study reported a diametrically opposite finding, whereby A-allele carriers of the same SNP had high levels of BPD symptoms when raised by depressed mothers and low levels when grown up in families with non-depressed mothers. GG homozygotes were unresponsive to early rearing conditions, suggesting that the SNP rs53576 of the OXTR gene could confer “differential susceptibility” to environmental contingencies . In keeping with differential susceptibility models, another study reported that girls were at greater risk of developing BPD symptoms when carrying at least on A allele of the SNP rs53576 and when experiencing childhood maltreatment, whereas maltreated boys were more vulnerable to developing BPD symptoms when being homozygous for the G/G allele .
The opposite genotypes were unresponsive to family environment in both sexes. Notably, among boys the G/G carriers were less likely to show BPD symptoms when growing up in non-maltreating family environments with no comparable effect in female A/A carriers, which led the authors to suggest that differential susceptibility occurs solely in boys .
In summary, these findings, though in part contradictory, suggest that variation of the OXTR gene is involved in individual differences in susceptibility to adversity and hence, the development of BPD symptoms. However, OT is certainly not the only, and most likely not the most important neuromodulator involved in the regulation of stress responsivity and LHS. In any event, it may nevertheless be helpful to consider the view that genetic polymorphisms involved in a psychiatric condition may not simply confer vulnerability, but possibly act in protective ways depending on early environment [24, 92]. As regards BPD, it is currently unclear whether individuals being at risk of developing the condition carry a larger than average number of plasticity alleles, which in combination with early adversity produce a BPD phenotype. Future genetic studies should address this question more explicitly.
The spectrum of comorbid disorders associated with BPD is mixed, with attention- deficit/hyperactivity disorder (ADHD) being suggestive of a fast LHS, whereas the case for posttraumatic stress disorder (PTSD) and depression is more complex. Studies suggest that comorbidity rates of these disorders with BPD are considerable [93, 94]. ADHD is associated with increased impulsivity, novelty-seeking and other externalizing features indicative of a fast LHS . PTSD seems to feature the extremes of variation of defense mechanisms akin to arrested flight, submission, freezing, and dissociation [96, 97]. Both PTSD and depression can be situated at both ends of the fast-slow LHS spectrum. As for the fast end, hypervigilance and highly reactive stress regulating mechanisms can have adaptive properties in dangerous environments (i.e. promoting a fast LHS), yet they may also bare the risk of dysfunction. Accordingly, PTSD and depression could be a costly consequence of a failure of stress regulation. Consistent with this interpretation, depression is more likely to occur in fast maturers, somatic symptoms associated with depression are linked with early adversity and depression in adolescence often co-occurs with externalizing behaviors, and generally with lower agreeableness, conscientiousness, and poor inhibitory control . Along similar lines, Belsky et al. have argued that internalizing problems – which are typical for many women with BPD – may ultimately serve to lower metabolism, increase body fat and thus initiate menarche earlier . It is equally plausible, however, to assign low mood a role in slow LHS, because it may shield an individual from pursuing unattainable goals and help avoid risks. With regard to BPD, either explanation may apply, that is, depression could be the cost for failure of a high-risk (fast) strategy, or a self-protective mechanism in the sense of down- regulating strategic action to cope with stress caused by a fast LH pattern.
Along similar lines, eating disorders may reside at both ends of the continuum of LHS, based on the relevance of sexual competition for mates. Accordingly, a slow LHS would promote females to desire a thinner body than what men perceive sexually most attractive, which in turn, would increase the woman’s value as a long-term mate . Consequently, slow LHS should be more characteristic of anorexia nervosa (AN) than bulimia nervosa (BN) .
Consistent with this hypothesis, BN is associated with earlier sexual maturation and activity; patients with BN also show more externalizing behaviors than patients with AN. In accordance, BPD seems to be more often associated with BN than AN . However, more evenly distributed comorbidity rates have been reported in other studies, e.g. .
Seen through the lens of Behavioral Ecology, there is abundant evidence in support of the idea that BPD reflects a pathological variant of a fast LHS . In addition, insights from research into the neuropsychology, personality traits, interpersonal behavior, neuroimaging findings and genetics of BPD corroborate this view. While there is still controversy over differences in prevalence rates of BPD in men and women, there is overwhelming evidence for the prediction from LHT suggesting that men show more aggressive and noncompliant behavior (akin to antisocial personality traits), whereas women more often show signs of internalizing behavior, including signs of depression and anxiety [101, 102]. Accordingly, male BPD is more often characterized by explosive temperamental features and higher levels of novelty seeking compared to female BPD .With regard to personality, antisocial traits or full-blown antisocial personality disorder is more common among men with BPD. In addition, men with BPD have more often than women comorbid substance use disorders. By comparison, women with BPD are more often diagnosed with comorbid eating disorders, depression and anxiety, and posttraumatic stress disorders, all of which is consistent with predictions from LHT [11,104].
Why is all this interesting in regard of public health issues? First, the behavioral ecological view on BPD may have important ramifications for the psychiatric treatment of this condition. For one, neuroimaging studies of BPD may be worth reconsidering. In contrast to the traditional “medical” perspective suggesting that deviations from a statistical norm represent “deficits” (i.e. brain damage), neuroimaging findings in BPD may, in fact, reflect complex adaptations to early adversity and thus serve stress-regulation purposes, which may be functional in dangerous and unpredictable environments, but dysfunctional in safer environments . So, in keeping with the Adaptive Calibration Model, a therapeutic stance could entail acknowledging that a patient’s personal history has impacted on his or her stress regulating mechanisms which include brain circuits involved in threat evaluation and prediction of future resource availability . This attitude is fundamentally different to a more fatalistic “brain damage” perspective. Of note, studies have shown that anatomical “abnormalities” found in patients with a history of childhood adversity are reversible upon psychotherapy, suggesting that functional or structural brain variation is not necessarily impervious to modification .
Along similar lines, LHT suggests that the one-sided view on psychiatric genetics (vulnerability concept) should, in part, be replaced by one that considers genetic variations as expression of plasticity “for better or worse”, depending on the interaction of genes with the environment [81, 107]. This is a crucial point, because the same allelic variation can promote a slow or a fast LHS, depending on early environmental contingencies, thus acting at both ends of the LHS spectrum . This view may have profound implications for the understanding of BPD, because BPD patients may actually be among the genetically most plastic individuals who, due to early adversity, have developed dysfunctional interpersonal strategies .
Another example for how interpretation can influence therapeutic perspectives comes from studies in BPD using neuroeconomic paradigms. Commenting on King-Casas et al.’s trust game study, Kishida et al. noted “borderline personality disorder confers a diminished capacity to represent expectations for social partners, and as a consequence individuals with BPD cannot take corrective action (social control signal) that might serve to re-establish cooperative interaction” (this author’s italics) [51, 109]. An alternative interpretation of the same finding that is in line with LHT suggests that, rather than reflecting a cognitive deficit, it is the motivational structure of patients with BPD that lead them not to take corrective action by reinstalling cooperation. That is, individuals whose inner working models suggest that others are untrustworthy may not be motivated to respond to attempts to entice them back into a cooperative relationship .
As regards psychotherapy in general, existing treatments for BPD patients that have proved to be effective – dialectic behavioral therapy (DBT), transference-focused therapy (TFT), mentalization-based treatment (MBT), as well as newer developments including metacognitive interpersonal therapy (MCT) and compassion-focused therapy (CFT) – have barely taken into account evolutionary aspects, with the exception of CFT [110, 111].
However, potential implications from LHT have entirely been disregarded so far. This review contends that it could help patients change interpersonal attitudes and expectations, as well as their “real-life” behavior, if they gained insight into the inappropriateness of their current behavior considering present-day environmental conditions. Put another way, a “fast and furious” LHS may make sense in unpredictable and dangerous conditions, but less so in relatively safe and reliable circumstances. Of course, this cannot simply be “taught”, but worked-through over time in insight-oriented psychotherapeutic approaches . As Fonagy put it, “we are likely to see behavioral organizations that we currently term personality disorders as age specific adaptations to biopsychosocial pressures, which are best treated by developmentally specific interventions” .
The behavioral ecological approach has several limitations in explanatory power. One is that BPD is a fairly heterogeneous syndrome. Given that five out of nine diagnostic criteria are necessary for a diagnosis, it also follows that two randomly picked patients with BPD may overlap in only one symptom . Accordingly, the LH model presented here may not fit all phenotypic variations of BPD.1 Moreover, human behavior is extraordinarily malleable and plastic, such that signs and symptoms change over time. In the case of BPD, features most indicative of a fast LHS such as risk-taking behavior, impulsivity and self-mutilation decline in severity with increasing age . This is also predictable from LHT, because LHS that aim at maximizing reproductive success early in life become less relevant with increasing age, and should be negligibly present beyond the reproductive lifespan, i.e. in post- menopausal women.
From a LH perspective, future research should aim at collecting quantitative data about survival, reproduction and gene replication in large clinical samples. These data should include a detailed description of the various behavioral phenotypes according to LHT criteria (beyond DSM diagnoses) and individuals’ early and current environmental conditions.
Although no such data exist to date, a large study of fecundity in different psychiatric disorders found that those conditions that qualify best as “fast” LHS , including bipolar disorder, substance abuse (and in part, depression) are not associated with reduced fecundity (or even better than average fecundity), while those that may follow a “slow” LHS (e.g., autism) are associated with reduced fecundity . To answer the question whether or not “subthreshold” or “diluted” phenotypes are associated with reproductive advantages or disadvantages, there is a need for epidemiological studies in large non-clinical samples that are well characterized according to character and personality dimensions.
Related to this, a final point of interest for public health concerns how psychiatric diagnoses are made. A LH perspective suggest that the decision over “disorder” versus “no disorder” is not a matter of unconditional veracity, but highly dependent on contextual including cultural factors . Potential implications for psychiatric nosology cannot be exhaustively discussed here, however, as the case of BPD may illustrate, the functional analysis of “problem behavior” in an evolutionary perspective may come to different conclusions compared to views from social science perspectives . A LH approach to psychiatric conditions does not imply that disorders are, in general, adaptive. On the contrary, it is explicitly contended that BPD is not an adaptive condition. However, sub-threshold phenotypical trait expression may be adaptive in specific (here, unpredictable) circumstances, especially when considering that “adaptive” in a biological sense does not entail well-being or physical and mental health .
“Dis-order” arises from the inappropriateness of cognitions, emotions and behavior in a given environmental context. This can leave long-lasting or even permanent marks on the central nervous system and the way interpersonal processes are “embodied”. Psychiatry needs to take on the challenge to not emphasize boundaries between “disease” and “normalcy”, particularly in light of waxing and waning weights assigned to the “bio”, the “psycho” and the “social” aspects of psychiatric conditions, whereby evolutionary approaches may be helpful to integrate these aspects into a more coherent framework for psychiatric conditions.
1 An alternative would be to develop a novel taxonomy of psychiatric disorders solely based on predictions from LHT, but such a re-launch “from scratch” would disregard that diagnostic systems such as the Diagnostic and Statistical Manual of Mental Disorders (DSM-5) have evolved just like “memes”, and so has medical education. Thus, it would put evolutionary approaches to psychiatric conditions at risk of not being seriously considered by clinicians at all.
I am indebted to Marco Del Giudice for his helpful comments on an earlier draft of this manuscript.
- American Psychiatric Association. DSM-5. Diagnostic and Statistical Manual of Mental Disorders (5th). Washington D.C, USA: American Psychiatric Association, 2013.
- Grant BF, Chou SP, Goldstein RB et al. Prevalence, correlates, disability, and comorbidity of DSM-IV borderline personality disorder: results from the Wave 2 National Epidemiologic Survey on Alcohol and Related Conditions. J Clin Psychiatry. 2008;69:533-45.
- Bowlby Attachment and Loss, Vol. 1. Attachment. New York: Basic Books, 1969.
- Agrawal HR, Gunderson J, Holmes B et al. Attachment studies with borderline patients: a review. Harv Rev Psychiatry 2004;12:94-104.
- Fonagy P, Target M, Gergely G. Attachment and borderline personality disorder. A theory and some evidence. Psychiatr Clin North Am 2000;23:103.
- Zweig-Frank H, Paris J. Parents’ emotional neglect and overprotection according to the recollections of patients with borderline personality disorder. Am J Psychiatry 1991;148:648-51.
- Bierer LM, Yehuda, R, Schmeidler, J, Mitropoulou, V et al. Abuse and neglect in childhood: relationship to personality disorder diagnoses. CNS Spectrum 2003;8:737- 54.
- Paris J, Zweig-Frank H. A critical review of the role of childhood sexual abuse in the etiology of borderline personality Can J Psychiatry 1992;37(2):125-28.
- Amad, A, Ramoz, N, Jardri, R, Gorwood, P. Genetics of borderline personality disorder: Systematic review and proposal of an integrative model. Neurosci Biobehav Rev 2014;40:6-19.
- Few, LR, Miller JD, Grand JD, Maples J et al. Trait-Based Assessment of Borderline Personality Disorder Using the NEO Five-Factor Inventory: Phenotypic and Genetic Support. Psychol Assess 2015 May 18. [Epub ahead of print].
- McCormick B, Blum N, Hansel R, Franklin JA et al. Relationship of sex to symptom severity, psychiatric comorbidity, and health care utilization in 163 subjects with borderline personality disorder. Compr Psychiatry 2007;48(5):406-12.
- Paris J, Gunderson J, Weinberg I. The interface between borderline personality disorder and bipolar spectrum disorders. Compr Psychiatry 2007;48(2):145-54.
- Barrachina J, Pascual JC, Ferrer M, Soler J et Axis II comorbidity in borderline personality disorder is influenced by sex, age, and clinical severity. Compr Psychiatry 2011;52(6):725-30. doi: 10.1016/j.comppsych.2010.11.009. Epub 2011 Feb 23.
- Bayes A, Parker G, Fletcher K. Clinical differentiation of bipolar II disorder from borderline personality disorder. Curr Opin Psychiatry 2014;27(1):14-20. doi: 10.1097/YCO.0000000000000021.
- Whalley HC, Nickson T, Pope M, Nicol K et al. White matter integrity and its association with affective and interpersonal symptoms in borderline personality disorder. Neuroimage Clin 2015;7:476-81. doi: 10.1016/j.nicl.2015.01.016. eCollection 2015.
- Zanarini MC, Frankenburg FR, Hennen J, Silk KR. The longitudinal course of borderline psychopathology: 6-year prospective follow-up of the phenomenology of borderline personality disorder. Am J Psychiatry 2003;160(2):274-83.
- Smoski MJ, Lynch TR, Rosenthal MZ, Cheavens JS et al. Decision-making and risk aversion among depressive adults. J Behav Ther Exp Psychiatry 2008;39(4):567-76. doi: 10.1016/j.jbtep.2008.01.004. Epub 2008
- Widiger TA, Weissman MM. Epidemiology of borderline personality disorder. Hosp Community Psychiatry 1991;42(10):1015-21.
- Paris J, Chenard-Poirier MP, Biskin R. Antisocial and borderline personality disorders revisited. Compr Psychiatry 2013;54(4):321-25. doi: 1016/j.comppsych.2012.10.006. Epub 2012 Nov 28.
- Sansone RA, Wiederman MW. Sex and age differences in symptoms in borderline personality symptomatology. Int J Psychiatry Clin Pract 2014;18(2):145-49. doi: 10.3109/13651501.2013.865755. Epub 2013 Dec
- Stearns SC. The evolution of life histories. Oxford, NY: Oxford University Press, 1992.
- Stearns SC. The Evolution of Life History Traits: A Critique of the Theory and a Review of the Data. Ann Rev Ecol Syst 1977;8:145-71.
- Ellis BJ, Figueredo AJ, Brumbach BH, Schlomer GL. The impact of harsh versus unpredictable environments on the evolution and development of life history strategies. Hum Nature 2009:20:204–
- Ellis BJ, Boyce WT, Belsky J, Bakermans-Kranenburg, MJ et al. Differential susceptibility to the environment: An evolutionary-neurodevelopmental theory. Dev Psychopathol 2011;23:7–
- Del Giudice M. An Evolutionary life history framework for psychopathology. Psychol Inq 2014;25:261-300.
- Bribescas RG, Ellison PT,Gray PB. Male life history, reproductive effort, and the evolution of the genus Homo. Curr Anthropol 2012;53:424–
- Del Giudice M, Ellis BJ, Shirtcliff EA. The Adaptive Calibration Model of stress responsivity. Neurosci Biobehav Rev 2011;35:1562-92.
- Feldman R, Gordon I, Zagoory-Sharon O. Maternal and paternal plasma, salivary, and urinary oxytocin and parent-infant synchrony: considering stress and affiliation components of human bonding. Dev Sci 2011;14:752-61.
- Belsky J, Steinberg L, Draper P. Childhood experience, interpersonal development, and reproductive strategy: An evolutionary theory of socialization. Child Dev 1991;62:647-70.
- Chisholm JS, Quinlivan JA, Petersen RW, Coall DA. Early stress predicts age at menarche and first birth, adult attachment, and expected lifespan. Hum Nature 2005; 16:233-65.
- Del Giudice M. Sex ratio dynamics and fluctuating selection on personality. J Theor Biol 2012;297:48-60.
- Chisholm JS. Attachment and time preference: Relations between early stress and sexual behavior in a sample of American university women. Hum Nature 1999;10,5- 83.
- Brüne M, Ghiassi V, Ribbert Does borderline personality reflect the pathological extreme of an adaptive reproductive strategy? Insights and hypotheses from evolutionary life-history theory. Clin Neuropsychiatry 2010;7:3-9.
- Boyce WT, Ellis BJ. Biological sensitivity to context: I. An evolutionary- developmental theory of the origins and functions of stress reactivity. Development and Psychopathology 2005;17:271-301.
- Carvalho Fernando S, Beblo T, Schlosser N, Terfehr K et al. Associations of childhood trauma with hypothalamic-pituitary-adrenal function in borderline personality disorder and major depression. Psychoneuroendocrinology 2012 Oct;37(10):1659-68.
- Murgatroyd C, Patchev AV, Wu Y, Micale V et al. Dynamic DNA methylation programs persistent adverse effects of early-life stress. Nat Neurosci 2009;12(12):1559-66.
- Jovev M, Green M, Chanen A, Cotton S et al. Attentional processes and responding to affective faces in youth with borderline personality features. Psychiatry Res 2012;199:44-50.
- Brüne, M, Ebert A, Kolb M, Tas C et al. Oxytocin influences avoidant reactions to social threat in adults with borderline personality disorder. Psychopharmacol 2013;28(6):552-61. Clin. Exp. 2013.doi: 10.1002/hup.2343.
- Gaher R., Hofman NL, Simons J, Hunsaker R. Emotion regulation deficits as mediators between trauma exposure and borderline symptoms. Cogn Ther Res 2013; 37:466-75.
- Dinsdale N, Crespi BJ. The borderline empathy paradox: evidence and conceptual models for empathic enhancements in borderline personality disorder. J Pers Disord 2013;27(2):172-95.
- Linehan MM. Cognitive-behavioral treatment for borderline personality New York: Guilford, 1993.
- Gunderson JG, Lyons-Ruth K. BPD’s interpersonal hypersensitivity phenotype: a gene-environment-developmental model. J Pers Dis 2008;22(1):22-41.
- Nicol K, Pope M, Sprengelmeyer R, Young AW et al. Social judgement in borderline personality disorder. PLoS One 2013;8(11):e73440.
- Ebert A, Kolb M, Heller J, Edel MA et al. Modulation of interpersonal trust in Borderline Personality Disorder by intranasal oxytocin and childhood trauma. Soc Neurosci 2013;8:305-13.
- Völker KA, Spitzer C, Limberg A, Grabe HJ et al. [Executive dysfunctions in female patients with borderline personality disorder with regard to impulsiveness and depression]. Psychother Psychosom Med Psychol 2009;59(7):264-72.
- Cloninger CR, Svrakic DM, Przybeck TR. The Temperament and Character Inventory (TCI): a guide to its development and use. St. Louis, MO: Center for Psychobiology of Personality, Washington University,
- Christie R, Geis Studies in machiavellianism. New York: Academic Press, 1970.
- Fossati A, Donati D, Donini M, Novella L et al. Temperament, character, and attachment patterns in borderline personality disorder. J Pers Disord 2001;15(5):390- 402.
- Láng A. Borderline Personality Organization predicts Machiavellian interpersonal tactics. Pers Individ Diff 2015;80:28-31.
- Wischniewski J, Brüne M. How do people with borderline personality disorder respond to norm violations? Impact of personality factors on economic decision- making. J Pers Dis 2013;27:531-46.
- King-Casas B, Sharp, C, Lomax-Bream L, Lohrenz T et al. The rupture and repair of cooperation in borderline personality Science 2008;321(5890): 806-810.
- Unoka Z, Seres I, Aspán N, Bódi N et al. Trust game reveals restricted interpersonal transactions in patients with borderline personality disorder. J Pers Dis 2009;23(4):399-409.
- Franzen N, Hagenhoff M, Baer N, Schmidt A et al. Superior ‘theory of mind’ in borderline personality disorder: an analysis of interaction behavior in a virtual trust game. Psychiatry Res 2011;187(1-2):224-33.
- Brüne, M. Textbook of evolutionary psychiatry and psychosomatic medicine. The origins of 2nd edn. New York, NY: Oxford University Press, 2015.
- Olesen TB, Jensen KE, Nygård M, Tryggvadottir L et al. Young age at first intercourse and risk-taking behaviours–a study of nearly 65 000 women in four Nordic countries. Eur J Public Health 2012;22(2):220-24.
- Sansone RA, Barnes J, Muennich E, Wiederman MW. Borderline personality symptomatology and sexual impulsivity. Int J Psychiatry Med 2008;38(1):53-60.
- Sansone RA, Chu JW, Wiederman MW. Sexual behaviour and borderline personality disorder among female psychiatric inpatients. Int J Psychiatry Clin Pract 2011;15(1):69-73. doi: 10.3109/13651501.2010.507871. Epub 2010 Sep
- Chen EY, Brown MZ, Lo TT, Linehan MM. Sexually transmitted disease rates and high-risk sexual behaviors in borderline personality disorder versus borderline personality disorder with substance use disorder. J Nerv Ment Dis 2007;195(2):125- 29.
- Harned MS, Pantalone DW, Ward-Ciesielski EF, Lynch TR et al. The prevalence and correlates of sexual risk behaviors and sexually transmitted infections in outpatients with borderline personality disorder. J Nerv Ment Dis 2011;199(11):832-38. doi: 10.1097/NMD.0b013e318234c02c.
- De Genna NM, Feske U, Larkby C, Angiolieri T et al. Pregnancies, abortions, and births among women with and without borderline personality disorder. Women’s Health Issues 2012;22(4):e371-77. doi: 1016/j.whi.2012.05.002.
- Labonte E, Paris J. Life events in borderline personality disorder. Can J Psychiatry 1993;38(10):638-40.
- Tragesser, SL, Benfield, J. Borderline personality disorder features and mate retention tactics. J Pers Dis 2012;26:334-44.
- Shackelford TK, Goetz AT, Buss DM, Euler HA et al. When we hurt the ones we love: Predicting violence against women from men’s mate retention. Pers Relationships 2005;12:447-63.
- Graber JA. Pubertal timing and the development of psychopathology in adolescence and beyond. Horm Behav 2013;64(2):262-9.
- Lien L, Dalgard F, Heyerdahl S, Thoresen M, Bjertness E. The relationship between age of menarche and mental distress in Norwegian adolescent girls and girls from different immigrant groups in Norway: results from an urban city cross-sectional survey. Soc Sci Med 2006;63(2):285-95.
- Sontag LM, Graber JA, Brooks-Gunn J, Warren MP. Coping with social stress: implications for psychopathology in young adolescent girls. J Abnorm Child Psychol 2008;36(8):1159-74. doi: 1007/s10802-008-9239-3.
- Burt SA, McGue M, DeMarte JA, Krueger RF, Iacono WG. Timing of menarche and the origins of conduct disorder. Arch Gen Psychiatry 2006;63(8):890-6.
- Stepp SD, Whalen DJ, Pilkonis PA, Hipwell AE et al. Children of mothers with borderline personality disorder: identifying parenting behaviors as potential targets for intervention. Personal Disord 2012;3(1):76-91.
- Rüsch N, Schulz D, Valerius G, Steil R et al. Disgust and implicit self-concept in women with borderline personality disorder and posttraumatic stress disorder. Eur Arch Psychiatry Clin Neurosci 2011;261(5):369-76.
- Tybur JM, Lieberman D, Griskevicius V. Microbes, mating, and morality: individual differences in three functional domains of disgust. J Pers Soc Psychol 2009;97(1):103-22. doi: 1037/a0015474.
- Teicher MH, Anderson CM, Polcari A. Childhood maltreatment is associated with reduced volume in the hippocampal subfields CA3, dentate gyrus, and subiculum. Proc Nat Acad Sci U S A 2012;109(9):563-72.
- Dannlowski U, Stuhrmann A, Beutelmann V, Zwanzger P et al. Limbic scars: long- term consequences of childhood maltreatment revealed by functional and structural magnetic resonance imaging. Biol Psychiatry 2012;71:286-93.
- Teicher MH, Andersen SL, Polcari A, Anderson CM et al. The neurobiological consequences of early stress and childhood maltreatment. Neurosci Biobehav Rev 2003;27(1-2):33-44.
- Wolf RC, Thomann PA, Sambataro F, Vasic N et al. Orbitofrontal cortex and impulsivity in borderline personality disorder: an MRI study of baseline brain perfusion. Eur Arch Psychiatry Clin Neurosci 2012;262(8):677-85.
- Monroe SM, Simons AD. Diathesis-stress theories in the context of life-stress research: Implications for the depressive disorders. Psycholol Bull 1991;110:406-25.
- Polanczyk G, Caspi A, Williams B, Price TS, et al. Protective Effect of CRHR1 Gene Variants on the Development of Adult Depression Following Childhood Maltreatment. Arch Gen Psychiatry 2009;66(9):978-85.
- Brüne M. Does the oxytocin receptor (OXTR) polymorphism (rs2254298) confer “vulnerability” for psychopathology or “differential susceptibility”? Insights from evolution. BMC Med 2012;10:38.
- Boyce WT, Chesney M, Alkon A, Tschann JM et al. Psychobiologic reactivity to stress and childhood respiratory illnesses: results of two prospective studies. Psychosom Med 1995;57(5):411-22.
- Belsky The development of human reproductive strategies: Promises and prospects.
- Belsky J, Jonassaint C, Pluess M, Stanton M et al. Vulnerability genes or plasticity genes? Molecular Psychiatry 2009;14:746-54.
- Belsky J, Beaver KM. Cumulative-genetic plasticity, parenting and adolescent self- regulation. J Child Psychol Psychiatry 2011;52(5):619-26.
- Rodrigues SM, Saslow LR, Garcia N, John OP, Keltner D. Oxytocin receptor genetic variation relates to empathy and stress reactivity in humans. Proc Nat’l Acad Sci USA 2009;106(50):21437-21441. doi: 1073/pnas.0909579106
- Chen FS, Kumsta R, von Dawans B et al. Common oxytocin receptor gene (OXTR) polymorphism and social support interact to reduce stress in humans. Proc Nat’l Acad Sci USA 2011;108(50):19937-19942. doi: 1073/pnas.1113079108
- Feldman R, Monakhov M, Pratt M, Ebstein RP. Oxytocin pathway genes; evolutionary ancient system impacting on human affiliation, sociality, and psychopathology, Biological Psychiatry. org/10.1016/j.biopsych.2015.08.008
- Walum H, Lichtenstein P, Neiderhiser JM et al. Variation in the oxytocin receptor gene is associated with pair-bonding and social behavior. Biol Psychiatry 2012;71(5):419-26.
- Meyer-Lindenberg A, Tost H. Neural mechanisms of social risk for psychiatric disorders. Nature Neuroscience 2012;15(5), 663-68. doi: 1038/nn.3083
- Bradley B, Westen D, Mercer KB et al. Association between childhood maltreatment and adult emotional dysregulation in a low-income, urban, African American sample: moderation by oxytocin receptor gene. Dev Psychopathol 2011;23:439-52. doi: 10.1017/S0954579411000162
- Bradley B, Davis TA, Wingo AP, Mercer KB, Ressler KJ. Family environment and adult resilience: contributions of positive parenting and the oxytocin receptor gene. Eur J Psychotraumatol 2013;4:21659. doi: 3402/ejpt.v4i0.21659
- McQuaid RJ, McInnis OA, Stead JD, Matheson K, Anisman A paradoxical association of an oxytocin receptor gene polymorphism: early-life adversity and vulnerability to depression. Frontiers Neurosci 2013;7:128. doi: 10.3389/fnins.2013.00128
- Hammen C, Bower JE, Cole SW. Oxytocin receptor gene variation and differential susceptibility to family environment in predicting youth borderline symptoms. J Pers Dis 2015;29(2):177-92. doi: 1521/pedi_2014_28_152
- Cicchetti D, Rogosch FA, Hecht KF, Crick NR, Hetzel S. Moderation of maltreatment effects on childhood borderline personality symptoms by gender and oxytocin receptor and FK506 binding protein 5 genes. Dev Psychopathol 2014;26(3):831-49. doi: 1017/S095457941400042X
- Bakermans-Kranenburg MJ, van Ijzendoorn MH. Research review: genetic vulnerability or differential susceptibility in child development: the case of attachment. J Child Psychol Psychiatry 2007;48(12):1160-73.
- Pagura J, Stein MB, Bolton JM, Cox BJ et al. Comorbidity of borderline personality disorder and posttraumatic stress disorder in the U.S. population. J Psychiatr Res 2010;44(16):1190-98.
- Luca M, Luca A, Calandra C. Borderline personality disorder and depression: an update. Psychiatr Q 2012;83(3):281-92.
- Del Giudice M. The Life History Model of psychopathology explains the structure of psychiatric disorders and the emergence of the p factor: A simulation study. Clin Psychol Sci 2015; DOI: 1177/2167702615583628
- Silove, D. Is posttraumatic stress disorder an overlearned survival response? An evolutionary learning hypothesis. Psychiatry 1998;61:181-90.
- Cantor C. Post-traumatic stress disorder: evolutionary perspectives. Aust N Z J Psychiatry 2009;43(11):1038-48.
- Abed RT, Metha S, Figueredo AJ, Aldridge S et al. Eating disorders and intrasexual competition: testing an evolutionary hypothesis among young women. Scientific World Journal 2012, Article ID 290813, 8 pages. doi: 10.1100/2012/290813. Epub 2012 Apr
- Rosenvinge JH, Martinussen M, Ostensen E. The comorbidity of eating disorders and personality disorders: a meta-analytic review of studies published between 1983 and 1998. Eat Weight Disord 2000;5(2):52-61.
- Chen EY, Brown MZ, Harned MS, Linehan MM. A comparison of borderline personality disorder with and without eating disorders. Psychiatry Res 2009;170(1):86-90.
- Skodol AE, Bender Why are women diagnosed with borderline more than men?
- Paris Gender differences in personality traits and disorders. Curr Psychiatry Rep2004;6(1):71-4.
- Sansone RA, Sansone LA. Personality Disorders: A nation-based perspective on prevalence. Innov Clin Neurosci 2011;8(4):13-8.
- Sansone RA, Sansone Borderline personality: a primary care context. Psychiatry 2004;1(2):19-27.
- Teicher MH, Anderson CM, Ohashi K, Polcari Childhood maltreatment: altered network centrality of cingulate, precuneus, temporal pole and insula. Biol Psychiatry 2014;76(4):297-305. doi: 10.1016/j.biopsych.2013.09.016.
- Davidson RJ, McEwen BS. Social influences on neuroplasticity: stress and interventions to promote well-being. Nat Neurosci 2012;15(5):689-95. doi: 10.1038/nn.3093.
- Brüne M, Belsky J, Fabrega H, Feierman JR et al. The crisis of psychiatry – insights and prospects from evolutionary theory. World Psychiatry 2012;11:55-7.
- Stanley B, Siever LJ. The interpersonal dimension of borderline personality disorder: toward a neuropeptide model. Am J Psychiatry 2010;167:24-39.
- Kishida KT, King-Casas B, Montague PR. Neuroeconomic approaches to mental disorders. Neuron 2010, 67(4):543-54.
- Bradley R, Conklin CZ, Westen D. Borderline personality disorder. In O’Donohue, W, Fowler K, Lilienfeld S (Eds.), Sage Handbook of Personality Disorders. Thousand Oaks, California: Sage 2007, 167-202.
- Gilbert P. The evolution and social dynamics of compassion. Soc Personal Psychol Compass, 2015;9(6):239-254. DOI: 1111/spc3.12176.
- Fonagy P. Editorial: Personality disorder. J Ment Health 2007;16(1):1-4.
- Douglas B. Disorders and its discontents. In: Woolfe, R, Strawbridge S, Douglas B, Dryden, W (Eds.). Handbook of counselling psychology. 3rd ed.: Thousand Oaks: Sage: 2009, 23-43.
- Morgan TA, Chelminski I, Young D, Dalrymple K, Zimmerman M. Differences between older and younger adults with borderline personality disorder on clinical presentation and impairment. J Psychiatr Res 2013;47(10):1507-13. doi: 10.1016/j.jpsychires.2013.06.009
- Del Giudice M. The life history model of psychopathology explains the structure of psychiatric disorders and the emergence of the p factor: A simulation study. Clin Psychol Sci DOI: 10.1177/2167702615583628
- Power RA, Kyaga S, Uher R, MacCabe JH, Långström N, Landen M, McGuffin P, Lewis CM, Lichtenstein P, Svensson AC. Fecundity of patients with schizophrenia, autism, bipolar disorder, depression, anorexia nervosa, or substance abuse vs their unaffected siblings. JAMA Psychiatry 2013;70(1):22-30. doi: 10.1001/jamapsychiatry.2013.268.
- Nesse Natural selection and the elusiveness of happiness. Phil Transact Royal Soc London B, Biol Sci 2004;359:1333-47.