Associations between stress reactivity and sexual and nonsexual risk taking in young adult human males

Glucocorticoids and Aggression: A Tripartite Interaction

The effects of glucocorticoids on aggression can be conceptualized based on its mechanisms of action. These hormones can affect cell function non-genomically within minutes, primarily by affecting the cell membrane. Overall, such effects are activating and promote both metabolic preparations for the fight and aggressive behavior per se. Chronic increases in glucocorticoids activate genomic mechanisms and are depressing overall, including the inhibition of aggressive behavior. Finally, excessive stressors trigger epigenetic phenomena that have a large impact on brain programming and may also induce the reprogramming of neural functions. These induce qualitative changes in aggression that are deemed abnormal in animals, and psychopathological and criminal in humans. This review aims at deciphering the roles of glucocorticoids in aggression control by taking in view the three mechanisms of action often categorized as acute, chronic, and toxic stress based on the duration and the consequences of the stress response. It is argued that the tripartite way of influencing aggression can be recognized in all three animal, psychopathological, and criminal aggression and constitute a framework of mechanisms by which aggressive behavior adapts to short-term and log-term changes in the environment.

Individual differences in the neuroendocrine response of male rats to emotional stressors are not trait-like and strongly depend on the intensity of the stressors

Biological response to stressors is critical to understand stress-related pathologies and vulnerability to psychiatric diseases. It is assumed that we can identify trait-like characteristics in biological responsiveness by testing subjects in a particular stressful situation, but there is scarce information on this issue. We then studied, in a normal outbred population of adult male rats (n = 32), the response of well-characterized stress markers (ACTH, corticosterone and prolactin) to different types of stressors: two novel environments (open-field, OF1 and OF2), an elevated platform (EP), forced swim (SWIM) and immobilization (IMO). Based on both plasma ACTH and prolactin levels, the OF1 was the lowest intensity situation, followed by the OF2 and the EP, then SWIM and finally IMO. When correlations between the individual responses to the different stressors were studied, the magnitude of the correlations was most dependent on the similarities in intensity rather than on other characteristics of stressors, with good correlations between similar intensity stressors and no correlations at all were found between stressors markedly differing in intensity. In two additional confirmatory experiments (n = 37 and n = 20) with HPA hormones, we observed good correlation between the response to restraint and IMO, which were close in intensity, and no correlation between OF1 and SWIM. The present results suggest that individual neuroendocrine response to a particular stressor does not predict the response to another stressor greatly differing in intensity, thus precluding characterization of low or high responsive individuals to any stressor in a normal population. The present data have important implications for human studies.

Psychopathic Traits and the Cheater-Hawk Hypothesis

The present study was a direct test of the cheater-hawk hypothesis which argues that psychopathy is related to two potentially adaptive interpersonal strategies: cheating and aggression. As expected, the measures of cheater and hawk behaviors comprised a single factor, according to a maximum-likelihood factor analysis. As hypothesized, psychopathic traits exhibited large positive correlations with measures of both cheater (entitlement, exploitiveness, and short-term mating orientation) and hawk (vengeance and aggression) behaviors. Furthermore, psychopathic traits were associated with the tendency of using individualistic and competitive tactics in an altruism game and being less likely to act in a prosocial manner. Finally, scores on the combined-cheater hawk variable were significantly correlated with psychopathic traits. As hypothesized, individuals scoring high on Factor 1 of psychopathy were more likely to utilize behaviors and strategies associated with the cheater-hawk designation, whether or not they scored high on Factor 2 of psychopathy. In general, the findings support the conceptualization that psychopathy represents a fast life-history strategy characterized by seeking personal gain over others, including exploitiveness (cheater), aggression (hawk), and risk taking. Results also indicate that cheater and hawk behaviors are part of a single strategy more often employed by those higher on psychopathic traits. Implications for treatment success are discussed.

Blunted cortisol reactivity and risky driving in young offenders - a pilot study

Adolescent risky driving is a significant burden on public health. Young offenders (i.e. under custody and supervision of the criminal justice system) may be particularly vulnerable, but research is scant. Previous work indicated that blunted cortisol reactivity to stress is a marker of risk-taking predisposition, including risky driving. In this study, we hypothesized that young offenders display higher levels of risky driving than a non-offender comparison group, and that cortisol reactivity contributes to the variance in risky driving independent of other associated characteristics (i.e. impulsivity, risk taking, alcohol and drug use). We found that young offenders (n = 20) showed riskier driving in simulation than comparison group (n = 9), and blunted cortisol reactivity was significantly associated with risky driving. The results suggest young offenders are prone to risky driving, and that individual differences in the cortisol stress response may be an explanatory factor.

Adherence to gender-typical behavior and high frequency substance use from adolescence into young adulthood

Substance use is prevalent among adolescents in the U.S., especially males. Understanding the cross-sectional and longitudinal associations between gender norms and substance use is necessary to tailor substance use prevention messages and efforts appropriately. This study investigates the relationship between adherence to gender-typical behavior (AGB) and substance use from adolescence into young adulthood. Participants in the National Longitudinal Study of Adolescent to Adult Health completed self-report measures on the frequency of binge drinking, cigarette smoking and marijuana use as well as various behaviors and emotional states that captured the latent construct of AGB. Sex-stratified logistic regression models revealed cross-sectional and longitudinal relationships between AGB and high frequency substance use. For example, an adolescent male who is more gender-adherent, compared to less adherent males, has 75% higher odds of high frequency binge drinking in adolescence and 22% higher odds of high frequency binge drinking in young adulthood. Sex-stratified multinomial logistic regression models also revealed cross-sectional and longitudinal relationships between AGB and patterns of use. For example, a more gender-adherent adolescent male, compared to one who is less adherent, is 256% more likely to use all three substances in adolescence and 66% more likely to use all three in young adulthood. Cross-sectional and longitudinal results for females indicate greater gender-adherence is associated with lower odds of high frequency substance use. These findings indicate adherence to gender norms may influence substance use behaviors across the developmental trajectory, and inform strategies for prevention efforts.

Cortisol boosts risky decision-making behavior in men but not in women

Acute stress may escalate risky decision-making in men, while there is no such effect in women. Although first evidence links these gender-specific effects of stress to stress-induced changes in cortisol, whether elevated cortisol is indeed sufficient to boost risk-taking, whether a potential cortisol effect depends on simultaneous noradrenergic activation, and whether cortisol and noradrenergic activation exert distinct effects on risk-taking in men and women is unknown. In this experiment, we therefore set out to elucidate the impact of cortisol and noradrenergic stimulation on risky decision-making in men and women. In a fully-crossed, placebo-controlled, double-blind design, male and female participants received orally either a placebo, hydrocortisone, yohimbine, an alpha-2-adrenoceptor-antagonist leading to increased noradrenergic stimulation, or both drugs before completing the balloon analogue risk task, a validated measure of risk-taking. Overall, participants' choice was risk-sensitive as reflected in reduced responding in high- compared to moderate- and low-risk conditions. Cortisol, however, led to a striking increase in risk-taking in men, whereas it had no effect on risk-taking behavior in women. Yohimbine had no such effect and the gender-specific effect of cortisol was not modulated by yohimbine. Our data show that cortisol boosts risk-taking behavior in men but not in women. This differential effect of cortisol on risk-taking may drive gender differences in risky decision-making under stress.

A Modified Trier Social Stress Test for Vulnerable Mexican American Adolescents

The Trier Social Stress Test (TSST) is a well validated and widely used social stressor that has been shown to induce a 2-4 fold increase in cortisol, the biological output produced by the Hypothalamic-Pituitary-Adrenal (HPA) axis in humans. While studies have explored how modifications to the TSST influence stress responsivity, few studies have created a modified TSST appropriate for vulnerable youth that elicits a significant cortisol stress response. Thus, the current study sought to modify or adjust the TSST in a culturally sensitive way for a vulnerable sample of 14 year-old adolescents. The present study took place within the context of a longitudinal birth cohort study of Mexican American families in California called the Center for the Health Assessment of Mothers and Children of Salinas (CHAMACOS). The CHAMACOS sample was optimal to test the effectiveness of a modified culturally appropriate TSST, as it is comprised of Mexican American youth, who are often excluded from research. These youths also have experienced significant early life adversity. Example modifications included timed prompts, alternative math tasks, use of same-ethnicity peers as confederates, debriefing immediately after the conclusion of the TSST, and using an unknown youth examiner to administer the debrief. Saliva samples were collected at baseline (after a resting phase), and then again at 15, 30, and 45 min post-TSST onset to assess cortisol concentration. A pilot study of 50 participants (50% female) have been analyzed for cortisol reaction to the TSST. Results confirmed that this modified version of the TSST was successful at eliciting a significant cortisol reaction, with a wide range of variability likely due to individual differences. Goals for modifications and ethnicity considerations are discussed. This study provides the foundation for future research to utilize a modified TSST with vulnerable youth.

Personality, coping, risky behavior, and mental disorders in the offspring of parents with bipolar disorder: a comprehensive psychosocial assessment

OBJECTIVES

It has been proposed that the offspring of parents with bipolar disorder (OBD), through genetic mechanisms and early family interactions, develop a heightened sensitivity to stress, maladaptive coping, and dysregulated behavior, which ultimately increases the risk for affective disorders. The current study tested certain predictions of this model by assessing different psychosocial and health-related outcomes in the OBD, including personality, coping style, smoking, suicidality, high-risk sexual behaviors, criminality, and mental health.

METHOD

The sample was composed of 74 OBD and 75 control offspring, who were between 14 and 27 years of age (mean: 19.38±3.56). Participants underwent a diagnostic interview and a structured interview to assess high-risk behavior and other maladaptive outcomes, and they completed the Revised NEO Personality Inventory and Coping in Stressful Situations questionnaire.

RESULTS

The rates of affective (31.1%) and non-affective (56.8%) disorders were elevated in the OBD compared to controls (9.5% and 32.4%). Relative to controls, OBD endorsed fewer task-oriented and more distraction coping strategies [Wilk׳s λ=.83, F(1, 136) =6.92, p<.01], and were more likely to report engaging in high-risk sexual behavior (OR=2.37; Wald=4.13, 1 df, p<05). Importantly, OBD reported elevated high-risk sexual behavior relative to controls, irrespective of affective disorder diagnosis.

CONCLUSION

The results highlight a potential risk profile for the OBD, consisting of ineffective coping strategies and risky sexual behavior and are discussed in the context of current knowledge of stress and coping in this population.

LIMITATIONS

The present findings were based on cross-sectional data and relied on offspring self-report. It would be useful to corroborate these findings with biobehavioural and longitudinal measures.

Impulsivity, risk taking, and cortisol reactivity as a function of psychosocial stress and personality in adolescents

Although adolescence is characterized by hormonal changes and increased disinhibited behaviors, explanations for these developmental changes that include personality and environmental factors have not been fully elucidated. We examined the interactions between psychosocial stress and the traits of negative emotionality and constraint on impulsive and risk-taking behaviors as well as salivary cortisol reactivity in 88 adolescents. In terms of behavioral outcomes, analyses revealed that negative emotionality and constraint were protective of impulsivity and risk taking, respectively, for adolescents in the no-stress condition; personality did not relate to either behavior in the stress condition. Low-constraint adolescents in the stress condition engaged in less risk taking than low-constraint adolescents in the no-stress condition, whereas there was no effect of stress group for high-constraint adolescents. In terms of cortisol reactivity, analyses revealed that low-constraint adolescents in the stress condition exhibited greater cortisol reactivity compared to high-constraint adolescents, which suggests that low-constraint adolescents mobilize greater resources (e.g., increased cognitive control, heightened attention to threat) in stressful situations relative to nonstressful ones. These results demonstrate that two facets of disinhibition and cortisol reactivity are differentially affected by psychosocial stress and personality (and their interactions) in adolescents.

Cortisol reactivity to psychosocial stress is greater in sexual risk takers

Several studies have reported an association between deviant behaviour and cortisol reactivity to stress. However, relatively few studies have investigated the relationship between psychobiological stress reactivity and sexual risk-taking behaviours. In this study, cortisol reactivity to the Trier Social Stress Test (TSST) was measured in 26 healthy young adults prior to the administration of a sexual health and behaviour questionnaire. The cortisol response to the TSST was greater in those individuals who reported that at least one of their previous two sexual partners was someone whom they had just met. Results are discussed in the context of a model which suggests that early life stress dysregulates the hypothalamic–pituitary–adrenal axis and increases the likelihood of later life risk-taking behaviour. The findings have implications in terms of improving our understanding of psychobiological factors which predispose individuals to engage in adverse sexual health behaviours.

Life events and sexual risk among HIV-negative, heterosexual, methamphetamine users

Identifying psychosocial factors associated with sexual risk behavior among methamphetamine users is essential to enhancing HIV and sexually transmitted infection prevention. This study examined the relationship between positive and negative life events and sexual risk behavior in a sample of 100 HIV-negative, heterosexually identified, methamphetamine-using men and women. Negative life event categories included death of a significant other, negative health event involving self or significant other, and child custody or visitation issues. Categories of positive life events included birth or pregnancy involving self or significant other, a positive relationship event, and a positive life change. Multivariate analyses demonstrated that negative life events were positively associated with total number of unprotected sex acts, whereas positive life events were not associated with sexual risk taking. Also, amount of methamphetamine used did not moderate the relationship between life events and sexual risk behavior. These data support future research to identify underlying mechanisms that link negative life events to sexual risk taking in this high-risk population.

Psychopathy and instrumental aggression: Evolutionary, neurobiological, and legal perspectives

In the study of aggression, psychopathy represents a disorder that is of particular interest because it often involves aggression which is premeditated, emotionless, and instrumental in nature; this is especially true for more serious types of offenses. Such instrumental aggression is aimed at achieving a goal (e.g., to obtain resources such as money, or to gain status). Unlike the primarily reactive aggression observed in other disorders, psychopaths appear to engage in aggressive acts for the purpose of benefiting themselves. This is especially interesting in light of arguments that psychopathy may represent an alternative life-history strategy that is evolutionarily adaptive; behaviors such as aggression, risk-taking, manipulation, and promiscuous sexual behavior observed in psychopathy may be means by which psychopaths gain advantage over others. Recent neurobiological research supports the idea that abnormalities in brain regions key to emotion and morality may allow psychopaths to pursue such a strategy-psychopaths may not experience the social emotions such as empathy, guilt, and remorse that typically discourage instrumentally aggressive acts, and may even experience pleasure when committing these acts. Findings from brain imaging studies of psychopaths may have important implications for the law.

Adaptive genetic variation, stress and glucose regulation

Elevated glucose levels in the presence of insulin are indicative of type 2 diabetes and the more inclusive metabolic syndrome. Alleles conferring susceptibility to these and other common conditions may be adaptations to past environments. It is possible that other mammals exhibiting environmental diversity harbor similar variants; therefore, we assessed glucose regulation in two species of deer mice (Peromyscus), a diverse endemic North American group. The prairie deer mouse, P. maniculatus bairdii (BW), and the Oldfield mouse, P. polionotus subgriseus (PO) differ in sexual dimorphism, behavior and habitat. PO animals exhibit better regulatory ability than BW animals, particularly among males, although both species display equivalent insulin levels/responses and non-fasted glucose levels. Hybrid males exhibit a PO glucose challenge response and subsequent analysis of consomic animals implicates Y chromosome variation as the genetic cause. Two pieces of evidence indicate that the male glucose regulatory differences are mediated by stress response: (1) fasting and handling alone account for most of the variation; (2) an inhibitor of glucocorticoid (GC) stress hormone synthesis eliminates these differences. PO males have GC levels that are twice those of BW males, indicating the presence of alleles that attenuate the GC response. We hypothesize that the interspecific physiological and behavioral differences are interrelated and that similar human variants exist.

Sexual behavior in young adulthood: a population-based twin study

OBJECTIVE

With behavior genetic analyses of data from young adult twins, we evaluated theoretical perspectives that differentially emphasize biological dispositions, social/cultural factors, or universal pathways to explain individual differences in sexual behaviors.

DESIGN

We fit biometric sex limitation models to three aspects of sexual behavior reported by 4,925 Finnish twins ages 23-27.

MAIN OUTCOME MEASURE

From a postal questionnaire, we obtained self-report information on initiation/abstinence of sexual intercourse, onset age, and number of sexual partners.

RESULTS

Genetic and non-shared environmental influences were significant for all three measures. There were trends for common environmental influences on initiation and, in females, age at first intercourse. Some differential effects in males and females were found. Results comparing onset age and number of partners among experienced twins from pairs concordant and discordant for initiation found genetic and environmental influences on initiation/abstinence overlapped those found for the other aspects of sexual behavior.

CONCLUSIONS

These results document genetic variation in individual differences in sexual behavior of young adults. Incorporating genetic dispositions into integrated models of sexual behavior will facilitate more effective health promotion and risk taking intervention.

Gene-environment contributions to young adult sexual partnering

To date, there has been relatively little work on gene-environment contributions to human sexuality, especially molecular analyses examining the potential contributions of specific polymorphisms in conjunction with life experiences. Using Wave III data from 717 heterozygous young adult sibling pairs included in the National Longitudinal Study of Adolescent Health, this article examined the combined contributions of attendance at religious services and three genetic polymorphisms (in the dopamine D4 receptor [DRD4]), dopamine D2 receptor [DRD2]), and the serotonin transporter promoter [5HTT]) to sensation seeking, a personality construct related to sexual behavior, and the number of vaginal sex partners participants had in the year before interview. Data analyses used an Allison mixed model approach to account for population stratification and correlated observations. DRD4 was unrelated to sensation seeking and to the number of sex partners in tests of both main effects and in interaction with religious attendance. Contrary to hypothesis, presence of the A1 DRD2 allele was associated with having had fewer sex partners in the past year. Associations between the 5HTT allele and sex partners varied by religious attendance, but again the patterns of associations were contrary to hypothesized relationships and were small in magnitude. These findings underscore the necessity of using more comprehensive multiple gene-multiple life experience approaches to investigations of complex behaviors such as sexual patterns.

Psychobiology of persistent antisocial behavior: Stress, early vulnerabilities and the attenuation hypothesis

Stress experienced during the sensitive prenatal, postnatal and early childhood periods of brain development can have damaging consequences for developing biological systems. Stressors imposed by early physical vulnerabilities and an adverse care giving environment is proposed to set in motion early precursors of later persistent antisocial behavior. The purpose of this report is to present an integrated theoretical perspective of potential mechanisms involved in the development of persistent antisocial behavior with an emphasis on early stressors and the neuroendocrinology of stress. The attenuation of endocrine physiology of the stress system is considered a key mechanism involved in persistent antisocial behavior. The amygdala is considered a structure/process linking subjective experiences, emotional learning, brain development and stress physiology. Attenuated cortisol level subsequent to early vulnerabilities is considered a risk marker for persistent antisocial behavior.

Dominance hierarchy influences adult neurogenesis in the dentate gyrus

Many mammalian species form dominance hierarchies, but it remains unknown whether differences in social status correspond to structural differences in the brain. Stressful experiences may arise naturally during the establishment of dominance, and stress has been linked to adult neurogenesis in the hippocampus. To determine whether position in a dominance hierarchy leads to changes in adult neurogenesis in the hippocampus, we examined the brains of rats housed in a visible burrow system (VBS), a seminaturalistic environment with opportunities for social interaction. Dominance hierarchies emerged among the males in all colonies within 3 d of living in the VBS. Although cell proliferation in the dentate gyrus did not differ between the groups, more new neurons were observed in the dentate gyrus of the dominant males compared with both subordinates and controls. Dominant and subordinate animals showed similar basal, stress, and recovery from stress levels of corticosterone, as well as similar thymus, adrenal gland, and body weights, suggesting that variables other than stress are responsible for the observed changes in adult neurogenesis. The differences in brain structure persisted among the animals that had no access to the burrow system after the dominance hierarchy stabilized, suggesting that social status rather than living in a complex environment accounts for the effect of dominance on adult neurogenesis.

Acute stressors and cortisol responses: a theoretical integration and synthesis of laboratory research

This meta-analysis reviews 208 laboratory studies of acute psychological stressors and tests a theoretical model delineating conditions capable of eliciting cortisol responses. Psychological stressors increased cortisol levels; however, effects varied widely across tasks. Consistent with the theoretical model, motivated performance tasks elicited cortisol responses if they were uncontrollable or characterized by social-evaluative threat (task performance could be negatively judged by others), when methodological factors and other stressor characteristics were controlled for. Tasks containing both uncontrollable and social-evaluative elements were associated with the largest cortisol and adrenocorticotropin hormone changes and the longest times to recovery. These findings are consistent with the animal literature on the physiological effects of uncontrollable social threat and contradict the belief that cortisol is responsive to all types of stressors.