Does central serotonergic function correlate inversely with aggression? A study using D-fenfluramine in healthy subjects

Association Between Polymorphism (5-HTTLPR) of the Serotonin Transporter Gene and Behavioral Response to Unfair Distribution

Behavioral responses to unfair distribution have been measured mainly using the Ultimatum Game (UG). Recent studies examining the biological basis of behavioral responses to unfair distribution have focused attention on the role of the serotonin transporter gene. However, studies, to date, have been conducted on non-Asians, and it has not been confirmed whether similar results can be seen in other ethnic groups. It has also been shown that behavioral responses to unfair distribution are not only seen in the case of victims themselves but also in the case of third parties not directly affected. This study aimed to determine whether the results of the previous study would be replicated in an Asian population and whether the serotonin transporter gene would also be associated with behavior toward unfair distribution by third parties. We examined the association between polymorphisms (5-HTTLPR) of the serotonin transporter gene and participants’ behavior in the UG and the third-party punishment game (TPPG). The results did not show an association between punishment for unfair proposals in the TPPG and genetic polymorphisms, while participants with the SL/LL genotype were more likely to reject unfair offers in the UG than those with the SS genotype. These results indicate that 5-HTTLPR is associated with behavior when unfair intentions are directed at oneself.

Anti-anger Effects of Herbal Medicine: A Mini-Review of Rat Studies

OBJECTIVE

To analyze the available data on the anti-anger effects of herbal medicines (HMs) as well as their underlying mechanisms in rat models.

METHODS

From 6 electronic databases [PubMed, EMBASE, China National Knowledge Infrastructure (CNKI), Wanfang, Oriental Medicine Advanced Searching Integrated System (OASIS), and Research Information Sharing Service (RISS)], relevant animal experiments were searched by using "anger," "rats," and "animal" as search keywords. The last search was conducted on November 22, 2019, and all experiments involving rat models of anger and treatment using HMs published until the date of the search were considered.

RESULTS

A total of 24 studies with 16 kinds of HMs were included. Most studies have used the "tail irritating method" and "social isolation and resident intruder" method to establish anger models. According to the included studies, the therapeutic mechanisms of HMs for anger regulation and important herbs by their frequency and/or preclinical evidence mainly incladed regulation of hemorheology (Bupleuri Radix, Paeoniae Radix Alba, and Glycyrrhizae Radix), regulation of sex hormones (Bupleuri Radix, Cyperi Rhizoma, and Paeoniae Radix Alba), regulation of neurotransmitters (Cyperi Rhizoma), regulation of anger-related genes (Bupleuri Radix, Glycyrrhizae Radix, and Paeoniae Radix Alba), and other effects. Overall, Liver (Gan) qi-smoothing herbs including Bupleuri Radix and Cyperi Rhizoma were the most frequently used.

CONCLUSIONS

This review found the frequent methods to establish an anger model, and major mechanisms of anti-anger effects of HMs. Interestingly, some Liver qi-smoothing herbs have been frequently used to investigate the anti-anger effects of HM. These findings provide insight into the role and relevance of HMs in the field of anger management.

Between Temperament and Psychopathology: Examples from Neuropharmacological Challenge Tests in Healthy Humans

BACKGROUND

This paper tries to demonstrate that the questionnaire-based continuum between temperament traits and psychopathology can also be shown on the biochemical level. A common feature is the incapacity to adapt to external demands, as demonstrated by examples of disturbed hormone cycles as well as neurotransmitter (TM) responses related to affective and impulse control disorders.

METHODS

Pharmacological challenge tests performed in placebo-controlled balanced crossover experiments with consecutive challenges by serotonin (5-HT), noradrenaline (NA), and dopamine (DA) agonistic drugs were applied to healthy subjects, and individual responsivities of each TM system assessed by respective cortisol and prolactin responses were related to questionnaire-based facets of depressiveness and impulsivity, respectively.

RESULTS

The depression-related traits "Fatigue" and "Physical Anhedonia" were characterized by low and late responses to DA stimulation as opposed to "Social Anhedonia," which rather mirrored the pattern of schizophrenia. Reward-related and premature responding-related impulsivity represented by high scores on "Disinhibition" and "Motor Impulsivity," respectively, as well as the questionnaire-based components of attention deficit hyperactivity disorder, "Cognitive" and "Motor Impulsivity," could be discriminated by their patterns of DA/NA responses. 5-HT responses suggested that instead of the expected low availability of 5-HT claimed to be associated with impulse control disorders, low NA responses indicated lack of inhibition in impulsivity and high NA responses in depression-related "Anhedonia" indicated suppression of approach motivation.

CONCLUSIONS

In spite of the flaws of pharmacological challenge tests, they may be suitable for demonstrating similarities in TM affinities between psychopathological disturbances and respective temperament traits and for separating sub-entities of larger disease spectra.

Sertraline as a treatment option for temper outbursts in Prader-Willi syndrome

Prader-Willi syndrome (PWS) is a rare neurodevelopmental disorder caused by lack of the paternal copy of maternally imprinted, paternally expressed genes at the chromosome 15q11-13 region. In most cases, it is caused by a paternal deletion or a maternal disomy of chromosome 15. Behavioral problems with temper outbursts are common and often combined with physical aggressiveness and self-injury. They are the most frequent cause for a reduced quality of life in adulthood and represent a serious challenge for the individual and those surrounding the individual in everyday life. Until now, no promising pharmaceutical treatment option has been established, and only a few case reports on treatment with selective serotonin reuptake inhibitors (SSRIs) have been reported. In this case series, we investigated the effect of the SSRI sertraline in 14 individuals with PWS frequently showing severe temper outbursts with aggressiveness and self-injuries. After 6 months of treatment with sertraline, 13 of 14 patients (92.6%) either no longer displayed temper outbursts or showed a significant decrease in frequency and severity of temper outbursts. In one case, treatment was stopped due to severe sleep abnormalities. We conclude that sertraline is a promising and safe treatment option for severe temper outbursts in patients with PWS.

Effects of maternal stress and perinatal fluoxetine exposure on behavioral outcomes of adult male offspring

Women of child-bearing age are the population group at highest risk for depression. In pregnant women, fluoxetine (Flx) is the most widely prescribed selective serotonin reuptake inhibitor (SSRI) used for the treatment of depression. While maternal stress, depression, and Flx exposure have been shown to effect neurodevelopment of the offspring, separately, combined effects of maternal stress and Flx exposure have not been extensively examined. The present study investigated the effects of prenatal maternal stress and perinatal exposure to the SSRI Flx on the behavior of male mice as adults.

METHODS

C57BL/6 dams exposed to chronic unpredictable stress from embryonic (E) day 4 to E18 and non-stressed dams were administered Flx (25 mg/kg/d) in the drinking water from E15 to postnatal day 12. A separate control group consisted of animals that were not exposed to stress or Flx. At 12 days of age, brain levels of serotonin were assessed in the male offspring. At two months of age, the male offspring of mothers exposed to prenatal stress (PS), perinatal Flx, PS and Flx, or neither PS or Flx, went through a comprehensive behavioral test battery. At the end of testing brain-derived neurotropic factor (BDNF) levels were assessed in the frontal cortex of the offspring.

RESULTS

Maternal behavior was not altered by either stress or Flx treatment. Treatment of the mother with Flx led to detectible Flx and NorFlx levels and lead to a decrease in serotonin levels in pup brains. In the adult male offspring, while perinatal exposure to Flx increased aggressive behavior, prenatal maternal stress decreased aggressive behavior. Interestingly, the combined effects of stress and Flx normalized aggressive behavior. Furthermore, perinatal Flx treatment led to a decrease in anxiety-like behavior in male offspring. PS led to hyperactivity and a decrease in BDNF levels in the frontal cortex regardless of Flx exposure. Neither maternal stress or Flx altered offspring performance in tests of cognitive abilities, memory, sensorimotor information processing, or risk assessment behaviors. These results demonstrate that maternal exposure to stress and Flx have a number of sustained effects on the male offspring.

Revisiting the serotonin-aggression relation in humans: a meta-analysis

The inverse relation between serotonin and human aggression is often portrayed as "reliable," "strong," and "well established" despite decades of conflicting reports and widely recognized methodological limitations. In this systematic review and meta-analysis, we evaluate the evidence for and against the serotonin deficiency hypothesis of human aggression across 4 methods of assessing serotonin: (a) cerebrospinal fluid levels of 5-hydroxyindoleacetic acid (CSF 5-HIAA), (b) acute tryptophan depletion, (c) pharmacological challenge, and (d) endocrine challenge. Results across 175 independent samples and over 6,500 total participants were heterogeneous, but, in aggregate, revealed a small, inverse correlation between serotonin functioning and aggression, anger, and hostility (r = -.12). Pharmacological challenge studies had the largest mean weighted effect size (r = -.21), and CSF 5-HIAA studies had the smallest (r = -.06). Potential methodological and demographic moderators largely failed to account for variability in study outcomes. Notable exceptions included year of publication (effect sizes tended to diminish with time) and self- versus other-reported aggression (other-reported aggression was positively correlated to serotonin functioning). We discuss 4 possible explanations for the pattern of findings: unreliable measures, ambient correlational noise, an unidentified higher order interaction, and a selective serotonergic effect. Finally, we provide 4 recommendations for bringing much needed clarity to this important area of research: acknowledge contradictory findings and avoid selective reporting practices; focus on improving the reliability and validity of serotonin and aggression measures; test for interactions involving personality and/or environmental moderators; and revise the serotonin deficiency hypothesis to account for serotonin's functional complexity.

Interaction between the serotonergic system and HPA and HPT axes in patients with major depression: implications for pathogenesis of suicidal behavior

Disturbances in the serotonin (5-hydroxytryptamine, 5-HT) system constitute the neurobiological abnormality most consistently associated with suicide. This abnormality could be a marker of vulnerability predisposing individuals to auto-aggressive and impulsive behavior. However, other abnormalities, such as hyperactivity of the hypothalamic-pituitary-adrenal (HPA) axis, have also been described in suicide victims. While inhibitory effects of adrenocorticosteroids on 5-HT_1A receptor function have been shown in animals, HPA axis hyperactivity does not seem to be responsible for the reduced 5-HT activity found in depressed patients with a history of suicidal behavior. On the other hand, hypothalamic-pituitarythyroid (HPT) axis dysfunction, frequently observed in depression, may represent a compensatory response to reduced central 5-HT neurotransmission. Moreover, in depressed patients with a history of suicidal behavior, the absence of a functional link between HPT and dopamine activity at the hypothalamic level may be implicated in the pathophysiology of suicidal behavior. Future research is needed to determine why compensatory mechanisms are not efficient in patients with suicidal behavior.

Effects of cocaine on maternal behavior and neurochemistry

Drug addiction is a chronic relapsing disorder that involves drug seeking and abuse despite the negative social and health consequences. While the potential effects of cocaine on child development have been extensively studied over the last 30 years, few researchers have focused on the effects of cocaine on maternal behavior, which includes offspring care and maternal aggression towards an unfamiliar individual. In humans, maternal cocaine use can lead to child neglect, abuse, and disrupt the mother-child bond. While it has been argued the developmental effects of maternal cocaine use on children were initially overstated, it is clear that disruptions of typical maternal behavior (i.e. postpartum depression, anxiety disorders) are detrimental to the physical and emotional health of offspring. Cocaine use in mothers is commonly associated with psychological disorders, including depression and anxiety, and it is postulated that many of the negative effects of maternal cocaine use on offspring are mediated through changes in maternal behavior. This review will summarize research on cocaine and maternal behavior in animal and human studies, discuss potential mechanisms, and suggest therapeutic strategies for treating cocaine-affected maternal behavior which may improve the physical and behavioral health of both mother and child. The primary objective is to stimulate future communication, cooperation, and collaboration between researchers who use animals and humans to study cocaine and maternal behavior.

Effects of acute tryptophan depletion on prefrontal-amygdala connectivity while viewing facial signals of aggression

BACKGROUND

Reduced levels of serotonin (5-HT) within prefrontal cortex (PFC)-amygdala circuits have long been implicated in impulsive aggression. However, whether lowering 5-HT alters the dynamic interplay between the PFC and the amygdala has not been directly tested in humans. It is known that manipulating 5-HT via acute tryptophan depletion (ATD) causes variable effects on brain responses to a variety of emotional stimuli, but it remains unclear whether ATD affects functional connectivity in neural networks involved in processing social signals of aggression (e.g., angry faces).

METHODS

Thirty healthy individuals were enrolled in a randomized, double-blind, placebo-controlled ATD study. On each treatment, brain responses to angry, sad, and neutral faces were measured with functional magnetic resonance imaging. Two methods (psycho-physiological-interaction in a general linear model and dynamic causal modeling) were used to assess the impact of ATD on the functional connectivity between PFC and amygdala.

RESULTS

Data from 19 subjects were available for the final analyses. A whole-brain psycho-physiological-interaction in a general linear model showed that ATD significantly modulated the connectivity between the amygdala and two PFC regions (ventral anterior cingulate cortex and ventrolateral PFC) when processing angry vs. neutral and angry vs. sad but not sad vs. neutral faces. Dynamic causal modeling corroborated and extended these findings by showing that 5-HT depletion reduced the influence of processing angry vs. neutral faces on circuits within PFC and on PFC-amygdala pathways.

CONCLUSIONS

We provide strong support for neurobiological accounts positing that 5-HT significantly influences PFC-amygdala circuits implicated in aggression and other affective behaviors.

Neurobiological and psychopathological variables related to emotional instability: a study of their capability to discriminate patients with bulimia nervosa from healthy controls

OBJECTIVE

To analyze the capability of a set of neurobiological and psychopathological variables to discriminate bulimia nervosa (BN) patients from healthy controls.

METHOD

Seventy-five female patients with purging BN and 30 healthy controls were compared for psychopathology (impulsivity, borderline personality traits, depressive symptoms and self-defeating personality traits) and neurobiological parameters reflecting hypothalamic-pituitary-adrenal axis activity (morning serum cortisol before and after dexamethasone) and monoamine activity (24-hour urinary excretion of norepinephrine, serotonin, dopamine, and their main metabolites: 3-methoxy-4-hydroxyphenylglycol, 5-hydroxyindoleacetic acid, and homovanillic acid). Furthermore, the relationships between the 2 sets of variables were compared in the 2 samples.

RESULTS

BN patients displayed higher impulsivity, more severe depressive features, and more borderline and self-defeating personality traits than controls. The 4 psychopathological variables were strongly interrelated in patients, whereas only depressive features correlated with self-defeating personality traits in controls. Patients had lower 24-hour excretion of serotonin and dopamine than controls, as well as lower ability to suppress cortisol. The relations between the biochemical and the psychopathological variables were only significant in the BN patients, but not in the control group. When discriminant analysis methods were applied, patients and controls differed for psychopathology (impulsive behaviors and borderline personality traits) and biological parameters (baseline cortisol and dopamine excretion), but when the variables were analyzed together, the differences in neurobiological parameters appeared as mediated by the psychopathological status.

DISCUSSION

Our results suggest that hypothalamic-pituitary-adrenal axis activity, dopamine activity and other biological parameters are worthy of further study as potential dimensional markers of BN, although they seem to depend on the psychopathological status of the patients, in such a way that the psychopathological items associated with emotional instability (impulsivity and borderline personality traits) seem to be more reliable as clinical markers at the time being.

Citalopram improves metabolic risk factors among high hostile adults: results of a placebo-controlled intervention

Hostility is associated with a number of metabolic risk factors for cardiovascular disease, including waist-hip ratio, glucose, and triglycerides. Along with hostility, many of these measures have also been shown to be associated with reduced central serotonergic function. We have previously reported that a citalopram intervention was successful in reducing hostility by self-report assessment (Kamarck et al., 2009). Here we examine the effects of this serotonergic intervention on metabolic risk factors in the same sample. 159 healthy adults with elevated hostility scores were randomized to citalopram or placebo for a 2-month period. Citalopram favorably changed metabolic risk factors, including waist circumference (p=.003), glucose (p=.02), HDL cholesterol (p=.04), triglycerides (p=.03), insulin sensitivity (p=.045) and diastolic blood pressure by automated assessment (p=.0021). All of these metabolic changes were significantly mediated by treatment-related changes in body mass index (in most cases, p<.01). In addition, the changes in blood glucose were significantly mediated by treatment-related changes in hostility (p<.05). Mechanisms accounting for these associations remain to be explored.

Is desire for social relationships mediated by the serotonergic system in the prefrontal cortex? An [(18)F]setoperone PET study

Social behavior and desire for social relationships have been independently linked to the serotonergic system, the prefrontal cortex, especially the orbitofrontal cortex (OFC), and the anterior cingulate cortex (ACC). The goal of this study was to explore the role of serotonin 5HT(2A) receptors in these brain regions in forming and maintaining close interpersonal relationships. Twenty-four healthy subjects completed the Temperament and Character Inventory (TCI) prior to undergoing [(18)F]setoperone brain positron emission tomography (PET) to measure serotonin 5HT(2A) receptor availability within the OFC (BA 11 and 47) and ACC (BA 32). We explored the relationship between desire for social relationships, as measured by the TCI reward dependence (RD) scale, and 5HT(2A) receptor non-displaceable binding potential (BP(nd)) in these regions. Scores of RD were negatively correlated with 5HT(2A) BP(nd) in the ACC (BA 32, r = -.528, p = .012) and OFC (BA 11, r = -.489, p = .021; BA 47, r = -.501, p = .017). These correlations were corroborated by a voxel-wise analysis. These results suggest that the serotonergic system may have a regulatory effect on the OFC and ACC for establishing and maintaining social relationships.

Citalopram intervention for hostility: results of a randomized clinical trial

Hostility is associated with an increased risk for cardiovascular disease (CVD). Because central serotonin may modulate aggression, we might expect selective serotonin reuptake inhibitors (SSRIs) to be effective in reducing hostility. Such effects have never been examined in individuals scoring high on hostility who are otherwise free from major Axis I psychopathology according to criteria in the Diagnostic and Statistical Manual of Mental Disorders (4th ed., Text Revision; American Psychiatric Association, 2000). A total of 159 participants (ages 30?50 years, 50% female) scoring high on 2 measures of hostility and with no current major Axis I diagnosis were randomly assigned to 2 months of citalopram (40 mg, fixed-flexible dose) or placebo. Adherence was assessed by electronic measurement and by drug exposure assessment. Treated participants showed larger reductions in state anger (Condition x Time; p = .01), hostile affect (p = 02), and, among women only, physical and verbal aggression (p = .005) relative to placebo controls. Treatment was also associated with relative increases in perceived social support (p = .04). The findings have implications for understanding the central nervous system correlates of hostility, its associations with other psychosocial risk factors for CVD, and, potentially, the design of effective interventions.

Mechanisms underlying aggressive and hostile behavior in amphetamine users

PURPOSE OF REVIEW

To review current evidence linking amphetamine use with aggression and to consider possible factors that might underlie this association.

RECENT FINDINGS

Although evidence that amphetamine use is related to increased levels of aggression continues to grow, the underlying processes or mechanisms remain somewhat elusive. In this review, three possible underlying factors are considered. Neurotoxic, pharmacological effects of amphetamine on the dopaminergic and serotonergic systems are related to aggressive, hostile behavior in both animal and human studies. Of particular interest is the converging evidence that amphetamine use is related to impairment in executive functions (including self-control) that are regulated by the prefrontal cortex. Taken together, these findings suggest that amphetamine users may have an impaired capacity to control or inhibit aggressive impulses. Furthermore, high levels of impulsivity related to amphetamine use may also play a role. Finally, amphetamine use is associated with increased positive symptoms of psychosis, particularly paranoia, that contribute to a perception of the environment as a hostile, threatening place.

SUMMARY

Taken separately, each of these factors may lead to an increase in aggression with increased use of amphetamine, but their interactive or synergistic effects may be particularly problematic.

Serotonergic function, two-mode models of self-regulation, and vulnerability to depression: what depression has in common with impulsive aggression

Evidence from diverse literatures supports the viewpoint that two modes of self-regulation exist, a lower-order system that responds quickly to associative cues of the moment and a higher-order system that responds more reflectively and planfully; that low serotonergic function is linked to relative dominance of the lower-order system; that how dominance of the lower-order system is manifested depends on additional variables; and that low serotonergic function therefore can promote behavioral patterns as divergent as impulsive aggression and lethargic depression. Literatures reviewed include work on two-mode models; studies of brain function supporting the biological plausibility of the two-mode view and the involvement of serotonergic pathways in functions pertaining to it; and studies relating low serotonergic function to impulsiveness, aggression (including extreme violence), aspects of personality, and depression vulnerability. Substantial differences between depression and other phenomena reviewed are interpreted by proposing that depression reflects both low serotonergic function and low reward sensitivity. The article closes with brief consideration of the idea that low serotonergic function relates to even more diverse phenomena, whose natures depend in part on sensitivities of other systems.

5-HTTLPR and gender moderate changes in negative affect responses to tryptophan infusion

Expression of the serotonin transporter is affected by the genotype of the 5-HTTLPR (short and long forms) as well as the genotype of the SNP rs25531 within this region. Based on the combined genotypes for these polymorphisms, we designated each allele as a high or low expressing allele according to established expression levels-resulting in HiHi, HiLo, & LoLo genotype groups for analysis. We evaluated effects of gender and the promoter genotype on induction of negative affect by intravenous infusion of L: -tryptophan (TRP). The protocol consisted of a day-1 sham saline infusion and a day-2 active TRP infusion. Models assessed 5-HTTLPR composite genotype and gender as predictors of change in ratings of negative emotion during TRP infusion. During sham infusion there were no significant changes from baseline in mood ratings. During TRP infusion all negative affect ratings increased significantly from baseline (P's < .02). The genotype x gender interaction was a significant predictor of depression-dejection (P = .013), and trended towards predicting anger-hostility (P = .084). Males in the HiHi group had greater increases in negative affect during infusion, compared to all groups except LoLo females, who also showed increased negative affect.

Associations among central nervous system serotonergic function and neuroticism are moderated by gender

Serotonergic dysregulation is associated with negative affect. Plasma prolactin responses to a tryptophan enhancement challenge are used as a measure of central nervous system serotonergic activity. We examined prolactin responses to a tryptophan challenge as they relate to the personality domains of neuroticism, extraversion, openness, agreeableness, and conscientiousness. Participants were 67 volunteers. Regression models assessed peak prolactin response to intravenous tryptophan infusion as a predictor of neuroticism, extraversion, openness, agreeableness, and conscientiousness. Prolactinxgender product terms were included to examine moderation by gender. Models were adjusted for baseline levels of prolactin, age, and race. Gender moderated the association between N and prolactin level (p<.03). Higher levels of N were associated with decreased levels of prolactin responses in females, whereas the opposite was true for males. Remaining personality domains were not related to prolactin levels. Findings add to literature suggesting the serotonin system functions differently, in important ways, in males and females.

Personality and body mass index: a cross-sectional analysis from the Miyagi Cohort Study

OBJECTIVE

Obesity is an increasingly prevalent public health problem worldwide, and is associated with a higher risk of developing various noncommunicable diseases. To further examine the association between personality and overweight, obesity, or underweight, we conducted a cross-sectional analysis in Japan. We hypothesized that extraversion and psychoticism would have a positive association with overweight, and that neuroticism and lie would have an inverse association with overweight, whereas the association between personality and underweight would be the reverse image of overweight.

METHODS

In 1990, 30,722 subjects (40-64 years of age) completed a self-administered questionnaire including body weight and height and the Japanese version of the Eysenck Personality Questionnaire-Revised Short Form. Multivariate logistic regression analysis was used to calculate odds ratios for overweight [body mass index (BMI)> or =25.0 kg/m2] or underweight (BMI<18.5) relative to each category on the personality subscale.

RESULTS

In men and women, extraversion and psychoticism had positive associations with overweight, whereas neuroticism had an inverse association. Lie had an inverse association with overweight in men. In men and women, only extraversion had an inverse association with underweight and neuroticism had a positive association with underweight.

CONCLUSION

Our findings indicate that personality is associated with both overweight and underweight. These results may provide clues to devising more effective measures for preventing overweight, obesity, or underweight or for weight control intervention.

Sex, aggression and impulse control: an integrative account

There is evidence that the male sex and a personality style characterized by low self-control/high impulsivity and a propensity for negative emotionality increase the risk for impulsive aggressive, antisocial and criminal behavior. This article aims at identifying neurobiological factors underlying this association. It is concluded that the neurobiological correlates of impulsive aggression act through their effects on the ability to modulate impulsive expression more generally, and that sex-related differences in the neurobiological correlates of impulse control and emotion regulation mediate sex differences in direct aggression. A model is proposed that relates impulse control and its neurobiological correlates to sex differences in direct aggression.

Polymorphism of the 5-HT(2A) receptor gene: association with stress-related indices in healthy middle-aged adults

Past research has concentrated on the stress system and personality in order to explain the variance found in cognitive performance in old age. A growing body of research is starting to focus on genetic polymorphism as an individual difference factor to explain the observed heterogeneity in cognitive function. While the functional mechanism is still under investigation, polymorphism of the 5-HT(2A) receptor gene (-1438A/G) has been linked to certain behavioral and physiological outcomes, including cortisol secretion, the expression of certain personality traits, and memory performance. It was the goal of the present study to investigate the association between the -1438A/G polymorphism and stress hormone secretion, stress-related psychological measures, and cognitive performance in a group of adults between the ages of 50 and 65. To examine these associations, 101 middle-aged adults were recruited, completed a battery of psychological questionnaires and were administered a battery of cognitive tasks that assess frontal lobe and hippocampal function. Basal and stress-reactive salivary cortisol levels were collected, at home and in the laboratory. Analyses on psychological measures showed that participants with the GG genotype reported significantly higher levels of neuroticism compared to the AG group and higher levels of depression and more emotion-based coping strategies compared to both the AG and AA group. In terms of cortisol secretion, the AA genotype was related to a significantly higher awakening cortisol response (ACR) compared to the AG and GG group and the GG genotype group displayed a greater increase in cortisol secretion following a psychosocial stressor compared to the two other groups. On measures of cognitive performance, the AA genotype group performed significantly better on a test of declarative memory and selective attention compared to the other two groups. Together, these results suggest that carriers of the GG genotype are more susceptible to low mood and display a greater potential for an overactive stress system, which may influence cognitive function in later years.

The neurobiological bases for development of pharmacological treatments of aggressive disorders

Violence and aggression are major causes of death and injury, thus constituting primary public health problems throughout much of the world costing billions of dollars to society. The present review relates our understanding of the neurobiology of aggression and rage to pharmacological treatment strategies that have been utilized and those which may be applied in the future. Knowledge of the neural mechanisms governing aggression and rage is derived from studies in cat and rodents. The primary brain structures involved in the expression of rage behavior include the hypothalamus and midbrain periaqueductal gray. Limbic structures, which include amygdala, hippocampal formation, septal area, prefrontal cortex and anterior cingulate gyrus serve important modulating functions. Excitatory neurotransmitters that potentiate rage behavior include excitatory amino acids, substance P, catecholamines, cholecystokinin, vasopressin, and serotonin that act through 5-HT(2) receptors. Inhibitory neurotransmitters include GABA, enkephalins, and serotonin that act through 5-HT(1) receptors. Recent studies have demonstrated that brain cytokines, including IL-1beta and IL-2, powerfully modulate rage behavior. IL-1-beta exerts its actions by acting through 5-HT(2) receptors, while IL-2 acts through GABAA or NK(1) receptors. Pharmacological treatment strategies utilized for control of violent behavior have met with varying degrees of success. The most common approach has been to apply serotonergic compounds. Others included the application of antipsychotic, GABAergic (anti-epileptic) and dopaminergic drugs. Present and futures studies on the neurobiology of aggression may provide the basis for new and novel treatment strategies for the control of aggression and violence as well as the continuation of existing pharmacological approaches.

Relations of serotonin function to personality: current views and a key methodological issue

Studies of biological underpinnings of personality suggest that serotonergic functioning relates to certain personality traits. However, how to interpret the findings depends partly on assumptions about how personality is organized. These assumptions are reflected in the assessment devices used and also in how the data are examined. Review of evidence to date appears to link serotonin function to impulsivity and, to some extent, to hostility. The relation of serotonin function to anxiety proneness is far more questionable. Indeed, when such a relation occurs, it often takes a form opposite to the direction argued by theory. It is recommended that research use measures that discriminate adequately among personality qualities reflecting incentive sensitivity, threat sensitivity, and impulsiveness. Indeed, it is highly desirable to examine facets of each of these qualities separately.

Emotion and Pain: A Functional Cerebral Systems Integration

Emotion and pain are psychological constructs that have received extensive attention in neuropsychological research. However, neuropsychological models of emotional processing have made more progress in describing how brain regions interact to process emotion. Theories of emotional processing can describe inter-hemispheric and intra-hemispheric interactions during emotional processing. Due to similarities between emotion and pain, it is thought that emotional models can be applied to pain. The following review examines the neuropsychology of emotion and pain using a functional cerebral systems approach. Specific comparisons are made between pain and anger. Attention is given to differences in cerebral function and physiology that may contribute to the processing of emotion and pain. Suggestions for future research in emotion and pain are given.

Does Serotonin Influence Aggression? Comparing Regional Activity before and during Social Interaction

Serotonin is widely believed to exert inhibitory control over aggressive behavior and intent. In addition, a number of studies of fish, reptiles, and mammals, including the lizard Anolis carolinensis, have demonstrated that serotonergic activity is stimulated by aggressive social interaction in both dominant and subordinate males. As serotonergic activity does not appear to inhibit agonistic behavior during combative social interaction, we investigated the possibility that the negative correlation between serotonergic activity and aggression exists before aggressive behavior begins. To do this, putatively dominant and more aggressive males were determined by their speed overcoming stress (latency to feeding after capture) and their celerity to court females. Serotonergic activities before aggression are differentiated by social rank in a region-specific manner. Among aggressive males baseline serotonergic activity is lower in the septum, nucleus accumbens, striatum, medial amygdala, anterior hypothalamus, raphe, and locus ceruleus but not in the hippocampus, lateral amygdala, preoptic area, substantia nigra, or ventral tegmental area. However, in regions such as the nucleus accumbens, where low serotonergic activity may help promote aggression, agonistic behavior also stimulates the greatest rise in serotonergic activity among the most aggressive males, most likely as a result of the stress associated with social interaction.

Platelet monoamine oxidase B (MAO-B) activity and its relationship to DL-fenfluramine-induced prolactin response in healthy men

Several techniques are used to assess central serotonergic neurotransmission in man, e.g. challenge tests (hormonal and physiological responses to serotonin active drugs), platelet MAO-B activity as well as brain imaging techniques. Little is known about how these tests relate to each other. The aim of the present study was therefore to investigate if platelet MAO-B activity could be related to hormonal and temperature responses to the serotonin active drug DL-fenfluramine in healthy men. Twelve male subjects without any history of psychiatric disorders or drug abuse/dependencies were recruited. Prior to the challenge with 60 mg DL-fenfluramine, which was given orally, blood for determination of platelet MAO-B activity was drawn. Blood samples for determination of serum prolactin and serum cortisol were drawn at baseline and thereafter every hour for the following six hours. In addition, body temperature was measured at the same time-points. Delta-values were calculated as the difference between the baseline values and the highest (prolactin and cortisol) or lowest value (temperature) thereafter. There was a strong positive correlation (r = 0.75, p < 0.02) between platelet MAO-B activity and Delta-prolactin. No correlations were found to Delta-cortisol, Delta-temperature or any of the baseline values. The results support the notion that the peripheral marker platelet MAO-B activity is related to the function of the central serotonergic neurotransmitter system as assessed by the prolactin response to 60 mg DL-fenfluramin.

Higher cortisol levels in spring and fall in patients with major depression

BACKGROUND

Multiple lines of evidence suggest that there are seasonal effects on mood and behavior, and that these effects are related to serotonergic and hypothalamic-pituitary-adrenal (HPA) function. This study sought to determine whether there is a seasonal effect on clinical parameters, baseline cortisol and prolactin levels, and cortisol and prolactin responses to fenfluramine administration in subjects with major depression.

METHODS

In all, 136 subjects with major depression entered the study. Sixty-two subjects who had a major depressive episode (MDE) in Spring or in Fall (the Spring/Fall group) were compared to 74 subjects who had MDE in Winter or in Summer (the Winter/Summer group). Demographic and clinical parameters were assessed and recorded. Clinical parameters included depression, aggression, impulsivity, hopelessness, hostility, and current suicide ideation rating scales, suicide attempt status, and number and maximum lethality of suicide attempts. Cortisol and prolactin levels were drawn before fenfluramine administration and hourly for 5 h thereafter. Cortisol and prolactin levels were computed as the area under the curve of hourly cortisol measurements.

RESULTS

Baseline cortisol levels were significantly higher in the Spring/Fall group compared to the Winter/Summer group (14.1+/-4.5 ng/ml vs. 12.5+/-4.4 ng/ml, df=132, t=2.16, p=0.03). There were no seasonal effects on baseline prolactin levels, or post-challenge cortisol and prolactin levels.

CONCLUSIONS

The Spring/Fall group and the Winter/Summer group may represent different subtypes of major depression. Future studies need to both confirm our results and elucidate the mechanism of the circannual effect on biological function in depressed patients. The results of our study underline the importance of considering seasonality in psychobiology.

Gender differences in a fenfluramine-activated FDG PET study of borderline personality disorder

Neuroimaging studies of impulsive-aggressive subjects with borderline personality disorder (BPD) demonstrate hypometabolism in areas of prefrontal and frontal cortex, and a blunted cortical metabolic response to challenge with serotonergic agonists. Neuroendocrine responses to serotonergic challenge are known to vary greatly by gender, and may be related to sex differences in expression of impulsive aggression. We conducted single-blind, placebo-controlled fenfluramine-activated positron emission tomography (PET) studies in impulsive male and female subjects with BPD to look for gender differences in cortical response. The sample comprised 22 BPD (15 female, 7 male) and 24 control subjects (10 female, 14 male) who received placebo on Day 1 and d,l-fenfluramine on Day 2 before PET neuroimaging. In response to placebo, female, but not male, controls had areas of increased uptake of fluorodeoxyglucose-F18 in prefrontal cortex compared with BPD subjects, with greatest uptake in the medial orbital frontal cortex, bilaterally. Male, but not female, BPD subjects, showed areas of increased glucose utilization compared with controls in large areas of parietal and occipital cortex, bilaterally. In response to fenfluramine (relative to placebo), significant decreases in glucose uptake were found in male, but not female, BPD subjects, centered in the left temporal lobe. Female, but not male, control subjects showed significantly decreased uptake in areas of right frontal and temporal cortex. Covarying for impulsive-aggression rendered nonsignificant the gender differences in responses to placebo or fenfluramine. Gender differences in serotonergic function may mediate differences in behavioral expression of impulsive aggression in subjects with BPD.

Two types of aggression are differentially related to serotonergic activity and the A779C TPH polymorphism

The authors investigated whether different types of aggression relate to the A779C tryptophan hydroxylase (TPH) polymorphism and to serotonergic activity in volunteers. A factor analysis of the Buss-Durkee Hostility Inventory yielded 2 factors representing Neurotic Hostility (NH) and Aggressive Hostility (AH). The authors used a neuroendocrine challenge with Citalopram in 48 volunteers and increased cortisol concentrations only in those with high levels of AH. Finally, an association study with 58 volunteers revealed that the A779C TPH polymorphism significantly relates to AH, with the highest aggression levels for the genotype AA and the lowest aggression levels for the genotype CC, but not to NH. Results are discussed with respect to inconsistent findings in the literature, which may be explained by this distinction of types of aggression.

Augmentation of serotonin enhances pleasant and suppresses unpleasant cortical electrophysiological responses to visual emotional stimuli in humans

The serotonergic system is one of the major systems targeted in the pharmacological treatment of a wide range of mood disorders including depression; however, little is known about the neurophysiological mechanisms underlying the effects of serotonin (5-HT) on affective phenomena including emotional behaviours, mood and emotional processing. The aim of the current study was to investigate how 5-HT acutely modulates steady-state visually evoked potentials (SSVEP), heart rate (HR) and verbal ratings associated with the viewing of differently valent emotional images. In a randomised double-blind, placebo-controlled design, 17 healthy subjects were tested under two acute treatment conditions: placebo and citalopram (20 mg) (a selective serotonin re-uptake inhibitor, or SSRI). Participants were tested 2 h post treatment whilst viewing 75 images (categorised as pleasant, neutral or unpleasant). Results indicate that under placebo treatment, processing of unpleasant valence [unpleasant (-) neutral images] was associated with decreases in SSVEP amplitude and latency in frontal and occipital cortices, whereas processing of pleasant valence [pleasant (-) neutral images] was associated with amplitude decreases and latency increases within frontal and left temporoparietal cortices. Decreases in both amplitude and latency are both interpreted as surrogate measures of cortical activation or excitation. Citalopram relative to placebo attenuated the electrophysiological activation to unpleasant valence within frontal and occipital cortices, but potentiated electrophysiological activation (amplitude only) to pleasant valence within parietooccipital cortices. Citalopram relative to placebo also suppressed differences in heart rate associated with the viewing of pleasant and unpleasant images, but did not alter subject's subjective responses to emotional images. Results suggest that responsiveness to pleasant and unpleasant stimuli following neurochemical modulation may vary across different response systems (i.e. self-report, HR and SSVEP). Electrophysiological findings suggest that acute serotonergic augmentation with citalopram modulates cortical processing of emotionally valent stimuli such that response to pleasant valence is potentiated and response to unpleasant valence is suppressed. The findings suggest a possible neurophysiological mechanism underlying antidepressant drug action on emotion.

An integrative approach to the neurophysiological substrates of social withdrawal and aggression

An integrative model of the neurophysiology of aggression and social withdrawal is proposed. A detailed overview of the limbic-hypothalamic-pituitary-adrenal (LHPA) axis is presented first, because we consider it to be a critical system that interacts with a variety of physiological processes to modulate affect-related behaviors. This detailed analysis of the LHPA axis is then used to clarify the research literature that links aggression and social withdrawal to LHPA functioning. We then review the role of amygdala and prefrontal cortex functioning in modulating aggression and social withdrawal. Particular attention is paid to how the amygdala and the prefrontal cortex interact with the LHPA system and the environment to produce specific behavioral tendencies throughout development. A brief overview of the implied methodological and theoretical model is provided. We explain how a detailed understanding of specific physiological processes is essential in order to develop appropriate research protocols. In addition, we suggest that future research should focus on the mapping of distinct integrative biosocial profiles that are related to specific behaviors during different developmental stages.

Interaction of nitric oxide and serotonin in aggressive behavior

Nitric oxide (NO) modulates many behavioral and neuroendocrine responses. Genetic or pharmacological inhibition of the synthetic enzyme that produces NO in neurons evokes elevated and sustained aggression in male mice. Recently, the excessive aggressive and impulsive traits of neuronal NO synthase knockout (nNOS-/-) mice were shown to be caused by reductions in serotonin (5-HT) turnover and deficient 5-HT1A and 5-HT1B receptor function in brain regions regulating emotion. The consistently high levels of aggression observed in nNOS-/- mice could be reversed by 5-HT precursors and by treatment with specific 5-HT1A and 5-HT1B receptor agonists. The expression of the aggressive phenotype of nNOS-/- knockout mice requires isolated housing prior to testing. The effects of social factors such as housing condition and maternal care can affect 5-HT and aggression, but the interaction among extrinsic factors, 5-HT, NO, and aggression remains unspecified. Taken together, NO appears to play an important role in normal brain 5-HT function and may have significant implications for the treatment of psychiatric disorders characterized by aggressive and impulsive behaviors.

Impulsivity and prefrontal hypometabolism in borderline personality disorder

Prefrontal hypoperfusion and decreased glucose uptake in the prefrontal cortex (PFC) are found in violent criminal offenders, murderers and aggressive psychiatric patients. These abnormalities may be independent of diagnosis and associated with impulsive-aggression as a personality trait. Impulsive-aggression is a clinical characteristic of borderline personality disorder (BPD) where it is associated with assaultive and suicidal behaviors. We conducted FDG-PET studies in 13 non-depressed, impulsive female subjects with BPD and 9 healthy controls to look for abnormalities in glucose metabolism in areas of the PFC associated with regulation of impulsive behavior. Statistical Parametric Mapping-99 (SPM99) was used to analyze the PET data with Hamilton depression scores as covariate. Significant reductions in FDG uptake in BPD subjects relative to healthy controls were found bilaterally in medial orbital frontal cortex, including Brodmann's areas 9, 10 and 11. There were no significant areas of increased uptake in BPD subjects compared to control subjects. Covarying for measures of impulsivity or impulsive-aggression rendered insignificant the differences between groups. Decreased glucose uptake in medial orbital frontal cortex may be associated with diminished regulation of impulsive behavior in BPD.

Impulsivity, gender, and response to fenfluramine challenge in borderline personality disorder

Behavioral impulsivity in borderline personality disorder (BPD) is associated with indices of diminished central serotonergic function, independent of suicidal behavior, depression or alcohol use disorder. Many of these studies have been conducted among males in specialized settings. Studies of BPD females, who constitute the majority of BPD patients, are generally conducted in community settings and report inconsistent findings. We studied gender differences in behavioral impulsivity and the prolactin response to D,L-fenfluramine (FEN) in BPD subjects in a community setting. A FEN challenge study was conducted with 64 BPD subjects (20 male, 44 female), and 57 controls (36 male, 21 female). Axis I and II disorders, including BPD, and suicidal histories were assessed by structured interviews. Controls were free of Axis I and II disorders. Impulsivity and aggression were assessed by the Buss-Durkee Hostility Inventory, Barratt Impulsiveness Scale, Minnesota Multiphasic Personality Inventory-Psychopathic Deviate subscale, and the Brown-Goodwin Lifetime History of Aggression. Male, but not female, BPD subjects had significantly diminished prolactin responses compared to controls. Impulsivity and aggression each predicted prolactin responses. A significant effect of BPD diagnosis on prolactin response was eliminated when impulsivity was co-varied. Impulsivity and aggression were inversely related to delta-prolactin and peak-prolactin responses among male but not female subjects. Gender differences in central serotonergic function may contribute to variations in impulsivity in BPD.

Possible association between serotonin transporter promoter region polymorphism and impulsivity in Koreans

Serotonin has become the major focus of biological studies of suicidal behavior and impulsive-aggressive behavior in humans. The serotonin transporter (5-HTT) gene is one of the important genes involved in the regulation of serotonin transmission. We examined the association of impulsivity in Korean populations with a functional polymorphism of the promoter region of the 5-HTT gene (5-HTTLPR). We recruited 186 adolescent prisoners and 64 medical students. Impulsivity was measured using the Barratt Impulsiveness Scale and we divided all subjects into three groups: impulsive subjects (IS, N=121), non-impulsive subjects (NIS, N=115) and an intermediate group (excluded, N=14). The 5-HTTLPR genotype was determined by polymerase chain reaction. All subjects were Korean men unrelated to each other. There were no significant differences in the genotype frequency of 5-HTTLPR-S/S, S/L and -L/L between the two groups in the Korean population (IS vs. NIS: 47.9 vs. 61.7%; 43.0 vs. 32.2%; and 9.1 vs. 6.1%, respectively). However, there was a statistically significant difference in allelic frequency of 5-HTTLPR-S and 5-HTTLPR-L between the two groups in the Korean population (IS vs. NIS: 69.4 vs. 77.8%; and 30.6 vs. 22.2%, respectively. From our results, this 5-HTTLPR polymorphism appears to be a possible candidate gene for impulsivity in the Korean population.

Sensory, hormonal, and neural control of maternal aggression in laboratory rodents

Parental animals of many rodent species display fierce and persistent aggression toward unfamiliar conspecifics that appears to protect their often altricial and defenseless young. We herein review studies of the sensory, hormonal, neuroanatomical, and neurochemical mechanisms underlying maternal aggression in laboratory rodents. The relationship between maternal aggression and fearfulness or anxiety is also discussed.

Serotonergic dysregulation in bipolar disorders: a literature review of serotonergic challenge studies

OBJECTIVES

Serotonin (5-hydroxytryptamine; 5-HT) and endocrine abnormalities have been repeatedly reported in bipolar disorders (BD). Useful methods to investigate 5-HT responsivity, and the interaction with neuroendocrine functioning, are provided by acute 5-HT challenge and depletion paradigms. In this review 5-HT challenges are limited to paradigms that stimulate 5-HT activity in BD.

METHODS

Literature was searched for in electronic libraries: MEDLINE and PSYCHLIT, period 1966-2001. Papers describing effects of an acute 5-HT challenge on neuroendocrine functioning in BD patients were selected.

RESULTS

Review of the literature revealed 15 studies: five papers described the effects of 5-HT challenges in manic BD patients, four papers in euthymic BD and seven in depressed BD patients. The reviewed 5-HT challenge paradigms are acute administration of oral and intravenous (i.v.) dosage of d,l-fenfluramine, tryptophan, 5-hydroxytryptophan, ipsapirone and buspirone. There were no papers which investigated neuroendocrine effects of m-chlorophenylpiperazine, clomipramine and citalopram in BD patients and were therefore not reviewed.

CONCLUSIONS

The literature on 5-HT challenge procedures in BD shows evidence for a blunted prolactin (PRL) in mania and depression as well as a blunted cortisol in euthymic BD patients. This suggests that in both mania and depression similar changes in the 5-HT system are involved. It is speculated that blunting of cortisol responses in euthymic BD patients may be a result of chronically altered 5-HT functioning, whereas changes in PRL release following 5-HT challenges reflect more state-dependent changes in 5-HT activity. The 5-HT responsivity in BD patients has also been associated with pharmacological treatment, suicidal behaviour, weight loss and age. Recommendations for future research are given.

Understanding the neurobiology of suicidal behavior

Our current knowledge about the neurobiology of suicide is still limited. Technical limitations and the complexity of the CNS are major obstacles. However, there is evidence for a hereditary disposition to suicide, which appears to be independent of diagnosis. Clinical, postmortem, genetic, and animal studies suggest that serotonin has a central role. The main regions of interest in the CNS have been the dorsal and median raphe nuclei in the midbrain that host the main serotonergic cell bodies and the prefrontal cortex, particularly the ventral PFC, innervated by the serotonergic system. In vivo and postmortem studies indicate serotonergic hypofunction in suicide and serious suicide attempts. This deficiency in turn can lead to a predisposition to impulsive and aggressive behavior, probably due to a breakdown in the inhibitory function of the ventral prefrontal cortex as a result of less serotonin input. In the context of this predisposition and the development of mental illness or other life stressors, the individual is at risk of acting on suicidal thoughts. Such deficient serotonin input into the PFC may arise as a result of genetic, parenting, head injury, and other effects. Identifying psychiatric, social, and environmental predictors of suicide are studied to improve prediction and prevention of suicide. A better understanding of the neurobiology of suicide can help detect at risk populations and help develop better treatment interventions.

Comparison between noradrenergic and serotonergic medications using the social adjustment scale: is drive enhancement necessary for recovery of social functioning?

The Social Adjustment Scale (SAS) was used to assess social functioning sequentially over 13 weeks in a group of 188 depressed outpatients randomized to either the noradrenergic antidepressant, nortriptyline, or the selective serotonin reuptake inhibitor, fluoxetine. Over the period of 13 weeks, there were no differences in total SAS scores between the nortriptyline and the fluoxetine group. In comparing the SAS subscale scores, which may measure different areas of motivation and behaviour (drive), there were differences between the two groups in only two subscales. At 13 weeks, the group randomized to fluoxetine were more impaired in marital role (p = 0.026) whereas, at 6 weeks, the group randomized to nortriptyline were more impaired in friction scores (p = 0.012). These results do not support the concept of specific augmentation of drive-related behaviour by noradrenergic medication. This challenges the earlier findings relating to drive enhancement and social adjustment using such medication.

Neurotransmitters, temperament and social functioning

Dimensional models can be usefully employed to describe both normal and disordered personality. Studies in molecular genetics, receptor binding, peripheral monoamines and pharmacological challenges have investigated the neurochemical basis of personality. Substantial evidence now exists to support a psychobiological model but the specificity of Cloninger's theory has not always been confirmed. Clinical studies have shown both temperament and character dimensions to improve with pharmacological treatment especially in treatment responders. Some personality changes are found to be independent of clinical effects and even to occur in normal subjects. Models of personality can help in predicting treatment outcome but individual dimensions may not be useful. It is hypothesised that social adaptation is related to the character dimensions and different sources of evidence link these to serotonergic actions. However, recent clinical studies have shown a specific effect of noradrenaline on self-perception and social motivation. Drugs with specific actions on different neurotransmitters may exert a distinctive pattern of effects on personality and social behaviour.

Lack of effect of HPA axis hyperactivity on hormonal responses to d-fenfluramine in major depressed patients: implications for pathogenesis of suicidal behaviour

There is evidence for inhibitory effects of adrenocorticosteroids on serotonergic (5-HT) activity. However, in depression the relationship between altered cortisol levels and brain 5-HT function remains to be clarified. The aim of this study was to investigate whether hypothalamic-pituitary-adrenal (HPA) axis hyperactivity is associated with 5-HT dysfunction in depressed patients, especially in those with suicidal behaviour. Cortisol levels following the dexamethasone suppression test (DST, 1 mg PO) and prolactin, corticotropin and cortisol responses to the d-fenfluramine test (d-FEN, 45 mg PO) - a specific 5-HT releaser/uptake inhibitor - were measured in 71 drug-free DSM-IV major depressed inpatients (40 with a history of suicide attempt, 31 without) and 34 hospitalized healthy control subjects. Depressed patients showed higher post-DST cortisol levels but similar responses to d-FEN compared with control subjects. Hormonal responses to d-FEN were not correlated with cortisol levels (basal or post-DST). Among the depressed patients, DST suppressors and DST nonsuppressors exhibited no significant difference in endocrine responses to d-FEN. However, patients with a history of suicide attempt, when compared with patients without such a history, showed lower hormonal responses to d-FEN but comparable basal and post-DST cortisol levels. Taken together these results suggest that, in depression, HPA axis hyperactivity is not responsible for the reduced 5-HT activity found in patients with a history of suicidal behavior.

Prolactin response to d-fenfluramine in postmenopausal women on and off ERT: comparison with young women

Estrogen is thought to have an impact on both psychological well being and cognitive function. The biological basis to this is not fully understood, but may involve estrogen's interactions with central serotonergic (5-HT) systems. Therefore, we studied the effect of long-term estrogen hormone replacement therapy (ERT) on central 5-HT tone in healthy postmenopausal women and made comparisons with young women. Prolactin (PRL) responses to the specific 5-HT releasing and re-uptake inhibiting agent, d-fenfluramine, were measured in three groups of healthy women: 11 young, 11 postmenopausal on long-term ERT, and 11 postmenopausal ERT naïve. PRL responses were significantly decreased in ERT naïve women compared to young healthy women. In contrast, PRL responses were not different between estrogen-treated and young women. Overall, there was a significant relationship between older age and lower PRL responsivity. These results suggest that central 5-HT tone is reduced in healthy postmenopausal women who are ERT naïve, but not in postmenopausal women who have received prolonged estrogen treatment. Estrogen may modulate age-related changes in 5-HT tone. This may partly explain why estrogen can decrease vulnerability to mood disorders and cognitive changes in postmenopausal women.

Plasma GABA levels correlate with aggressiveness in relatives of patients with unipolar depressive disorder

Plasma gamma-aminobutyric acid (GABA) levels are decreased in some patients with depression, mania and alcoholism. Medications which increase plasma GABA improve symptoms of mood disorders and can decrease aggression. We examined the relationship between plasma GABA and aggressiveness on the Buss-Durkee Hostility Inventory in 77 psychiatrically healthy adults. In subjects selected for having a first-degree relative with primary unipolar depressive disorder (FH+, n=33), plasma GABA was negatively correlated with aggressiveness (beta=-0.338, P=0.036), as was age (beta=-0.483, P=0.005). A relationship between plasma GABA levels and aggressiveness was not observed in subjects with no such family history (FH-, n=44). Moreover, FH+ subjects had significantly lower plasma GABA concentrations than FH- subjects. These data suggest that low GABA levels may correlate with some aspects of aggressiveness and may be genetically regulated.

The effects of the introduction of medication on the psychoanalytic process: a case study

The past fifteen years have seen a marked change in the attitude of psychoanalysts toward the use of medication in psychoanalysis, yet few detailed case studies have appeared in which the effects of the introduction of a medication on the psychoanalytic process have been studied. A plea for fluoxetine (Prozac) as a weight-loss aid, from a female patient whose analysis had progressed satisfactorily, set in motion a remarkable series of events. Her mood brightened, she rapidly lost weight, and she ultimately realized that she had the fantasy of being impregnated, all of which represented the reenactment of crucial childhood experiences. The most significant change in the psychoanalytic process was a newfound ability to experience critical thoughts and feelings, which previously had been prohibited by her harsh superego. At first both patient and analyst believed that the medication had "softened" her superego, but reexamination of the data revealed that most, if not all, of the changes could be attributed to the transference meaning of the collaboration rather than to the effects of the drug.

A regulatory polymorphism of the monoamine oxidase-A gene may be associated with variability in aggression, impulsivity, and central nervous system serotonergic responsivity

This study presents preliminary evidence of an association between polymorphic variation in the gene for monoamine oxidase-A (MAOA) and interindividual variability in aggressiveness, impulsivity and central nervous system (CNS) serotonergic responsivity. An apparently functional 30-bp VNTR in the promoter region of the X-chromosomal MAOA gene (MAOA-uVNTR), as well as a dinucleotide repeat in intron 2 (MAOA-CAn), was genotyped in a community sample of 110 men. All participants had completed standard interview and questionnaire measures of impulsivity, hostility and lifetime aggression history; in a majority of subjects (n=75), central serotonergic activity was also assessed by neuropsychopharmacologic challenge (prolactin response to fenfluramine hydrochloride). The four repeat variants of the MAOA-uVNTR polymorphism were grouped for analysis (alleles '1+ 4' vs. '2+3') based on prior evidence of enhanced transcriptional activity in MAOA promoter constructs with alleles 2 and 3 (repeats of intermediate length). Men in the 1/4 allele group scored significantly lower on a composite measure of dispositional aggressiveness and impulsivity (P<0.015) and showed more pronounced CNS serotonergic responsivity (P<0.02) than men in the 2/3 allele group. These associations were also significant on comparison of the more prevalent one and three alleles alone (encompassing 93% of subjects). Although in linkage disequilibrium with the MAOA-uVNTR polymorphism, MAOA-CAn repeat length variation did not vary significantly with respect to behavior or fenflluramine challenge in this sample. We conclude that the MAOA-uVNTR regulatory polymorphism may contribute, in part, to individual differences in both CNS serotonergic responsivity and personality traits germane to impulse control and antagonistic behavior.