Personality traits and leptin.

OBJECTIVE: Personality traits related to high neuroticism and low conscientiousness are consistently associated with obesity. Hormones implicated in appetite and metabolism, such as leptin, may also be related to personality and may contribute to the association between these traits and obesity. The present research examined the association between leptin and Five Factor Model personality traits. METHODS: A total of 5214 participants (58% women; mean [standard deviation] age = 44.42 [15.93] years; range, 18-94 years) from the SardiNIA project completed the Revised NEO Personality Inventory, a comprehensive measure of personality traits, and their blood samples were assayed for leptin. RESULTS: As expected, lower conscientiousness was associated with higher circulating levels of leptin (r = -0.05, p < .001), even after controlling for body mass index, waist circumference, or inflammatory markers (r = -0.05, p < .001). Neuroticism, in contrast, was unrelated to leptin (r = 0.01, p = .31). CONCLUSIONS: Individuals who are impulsive and lack discipline (low conscientiousness) may develop leptin resistance, which could be one factor that contributes to obesity, whereas the relation between a proneness to anxiety and depression (high neuroticism) and obesity may be mediated through other physiological and/or behavioral pathways.

Salivary cortisol levels in Parkinson's disease and its correlation to risk behaviour.

OBJECTIVE: To investigate salivary cortisol samples in patients with Parkinson's disease (PD) with and without impulsive compulsive behaviours (ICB) during a risk task. METHODS: Salivary cortisol levels were measured in 13 PD patients without ICB (PD-ICB) and in 15 PD patients with ICB (PD+ICB) before, after medication and throughout the day, and were compared with results with 14 healthy controls. All participants also performed a gambling task to assess risk taking behaviour. RESULTS: Significantly higher diurnal cortisol levels were found in the PD-ICB group compared with healthy controls but no differences were seen between the PD+ICB and the control group. Increased cortisol levels were significantly correlated with increased risk taking in PD+ICB patients but no interaction was found in the PD-ICB group. CONCLUSIONS: The findings are in keeping with previous studies which have linked low cortisol levels with antisocial behaviour. The higher cortisol levels during the risk task in the PD+ICB group are consistent with reports in pathological gamblers during gambling and addicts during drug abuse. The results support the hypothesis that cortisol plays an important role in risk taking in ICBs.

Low cholesterol is a risk factor for attentional impulsivity in patients with mood symptoms.

This study examined the relationship between cholesterol levels and impulsivity in a large sample of patients with mood symptoms. Three hundred and one patients with mood, anxiety, and personality disorders completed a battery of psychometric scales including the Barratt Impulsiveness Scale-Version 11 (BIS-11) and the Profile of Mood States (POMS). On the same day of psychometric assessment, blood samples were analyzed for total cholesterol (TC) and high-density lipoprotein cholesterol (HDL-C). Statistical analysis controlling for the confounding effects of age, gender, diagnosis, and current mood symptoms showed that lower TC levels were associated with increased attentional impulsivity. There was a weak linear correlation between TC and attentional impulsivity across the entire range of TC levels (110-295mg/dL) but a highly significant difference between participants with TC levels lower than 165mg/dL and the rest of the sample. The current study adds to the growing body of evidence pointing to the association between serum cholesterol and mental health. Considering that attentional impulsivity is a demonstrated risk factor for suicide, patients presenting with low cholesterol and mood symptoms may warrant increased clinical attention and surveillance.

High neuroticism and low conscientiousness are associated with interleukin-6.

BACKGROUND: High Neuroticism and low Conscientiousness are frequently implicated in health-risk behaviors, such as smoking and overeating, as well as health outcomes, including mortality. Their associations with physiological markers of morbidity and mortality, such as inflammation, are less well documented. The present research examines the association between the five major dimensions of personality and interleukin-6 (IL-6), a pro-inflammatory cytokine often elevated in patients with chronic morbidity and frailty. METHOD: A population-based sample (n=4923) from four towns in Sardinia, Italy, had their levels of IL-6 measured and completed a comprehensive personality questionnaire, the NEO-PI-R. Analyses controlled for factors known to have an effect on IL-6: age; sex; smoking; weight; aspirin use; disease burden. RESULTS: High Neuroticism and low Conscientiousness were both associated with higher levels of IL-6. The findings remained significant after controlling for the relevant covariates. Similar results were found for C-reactive protein, a related marker of chronic inflammation. Further, smoking and weight partially mediated the association between impulsivity-related traits and higher IL-6 levels. Finally, logistic regressions revealed that participants either in the top 10% of the distribution of Neuroticism or the bottom 10% of conscientiousness had an approximately 40% greater risk of exceeding clinically relevant thresholds of IL-6. CONCLUSIONS: Consistent with the literature on personality and self-reported health, individuals high on Neuroticism or low on Conscientiousness show elevated levels of this inflammatory cytokine. Identifying critical medical biomarkers associated with personality may help to elucidate the physiological mechanisms responsible for the observed connections between personality traits and physical health.

Negative association between plasma cortisol levels and aggression in a high-risk community sample of adolescents.

In this study, the association of aggressive behavior and personality traits with plasma cortisol levels was investigated in a high-risk community sample of adolescents. Plasma cortisol levels were collected in 245 fifteen-year-olds (118 males, 127 females) from an epidemiological cohort study of children at risk for psychopathology. Additionally, measures of reactive and proactive aggression, externalizing behavior and callous-unemotional together with impulsive personality features were assessed. Both subtypes of aggression as well as delinquent behavior and impulsive personality traits showed significant negative correlations with plasma cortisol levels. This association was observed in males, but not in females. In both gender groups, callous-unemotional traits were unrelated to plasma cortisol levels. This result suggests that the association between cortisol levels and aggression in adolescents is mediated rather by impulsivity than by unemotional or psychopathic traits.

Platelet serotonin concentration in children with attention-deficit/hyperactivity disorder.

BACKGROUND: Attention-deficit/hyperactivity disorder (ADHD) is a psychiatric disorder highly prevalent in children. The neurobiology of ADHD is still not clear, but is assumed to be related to disturbances in catecholaminergic and serotonergic (5-hydroxytryptamine, 5-HT) systems. Peripheral indices of central 5-HT function were shown in recent studies to be lower, unaltered, or increased in ADHD. METHODS: The study determined platelet 5-HT concentration in 84 medication-free 9-year-old (range 4-14 years) boys and girls with DSM-IV diagnosis of ADHD, subdivided according to the different symptoms (inattention, hyperactivity, and impulsivity) and clinical ADHD subtypes (predominantly hyperactive, predominantly inattentive, and combined subtype), and in 30 age- and sex-matched healthy controls. RESULTS: Children with ADHD had similar platelet 5-HT concentrations to control children. Platelet 5-HT concentration did not differ between boys and girls, or between children with a hyperactive, inattentive, or combined subtype of ADHD. In children with ADHD there was a significant positive correlation between platelet 5-HT concentration and impulsive symptoms, but not with symptoms of inattention or hyperactivity.Platelet 5-HT concentration wassignificantly higher in impulsive compared to non-impulsive children with ADHD. CONCLUSION: The data provide preliminary evidence that increased platelet 5-HT concentration might be a trait marker predictive of impulsivity in ADHD.

A test of alcohol dose effects on multiple behavioral measures of impulsivity.

BACKGROUND: Acute alcohol administration affects impulsive behavior, although these effects vary as a function of alcohol dose, assessment instrument, and time of measurement following administration. METHODS: We concurrently examined the dose-dependent effects of alcohol on three distinct types of impulsivity tasks (continuous performance [IMT], stop-signal [GoStop], and delay-discounting [SKIP] tasks). Ninety healthy alcohol drinkers were assigned to one of the three task groups (n=30 each), each group experienced placebo, 0.2, 0.4, 0.6, and 0.8 g/kg alcohol doses across 5 experimental days, and task performance was assessed at 0.5h before and 0.25, 1.0, and 2.0 h after alcohol administration. We hypothesized that impulsive responding on all tasks would be increased by acute alcohol administration both across time and during the peak BrAC, but the magnitude would depend on the task being tested. Analyses included the time course and the peak BrAC effects. Task comparisons of peak behavioral changes following each dose are illustrated using standardized scores. RESULTS: While alcohol consumption increased impulsive responding during all three tasks to some extent, our hypothesis was only partially supported. During the IMT, the 0.6 and 0.8 g/kg doses produced increased impulsive responding across time and at the peak BrAC. However, during the GoStop and SKIP, impulsivity increased across time regardless of the alcohol dose size, with no differences in impulsive responding among dose conditions at peak BrAC. CONCLUSIONS: This study demonstrated alcohol-induced changes in impulsivity are not uniformly affected by alcohol. These data, in conjunction with previous studies, further support that impulsivity is not a unitary construct.

Serum omega-3 fatty acids are associated with variation in mood, personality and behavior in hypercholesterolemic community volunteers.

Low dietary intake of omega-3 polyunsaturated fatty acids has been linked to several features of psychiatric symptomatology, including depression, disorders of impulse control, and hostility. Preliminary intervention trials of omega-3 fatty acid supplementation for clinical depression and other disorders have reported benefit. However, few studies have investigated the relationships between these fatty acids and normative variability in mood, behavior and personality. Participants were 105 hypercholesterolemic, but otherwise healthy, non-smoking adults. Fasting serum alpha-linolenic (alpha-LNA), eicosapentaenoic (EPA) and docosahexaenoic acid (DHA) were assayed with gas chromatography. Participants completed the Beck Depression Inventory (BDI), the NEO Five Factor Personality Inventory (NEO-FFI) and the Barratt Impulsiveness Scale (BIS). In multivariate analyses, higher levels of the long chain omega-3 PUFAs, EPA and DHA, were associated with significantly reduced odds of scoring >or=10 on the BDI. Similarly, DHA and EPA covaried inversely with NEO-Neuroticism scores, whereas DHA was positively associated with NEO-Agreeableness. On the BIS, DHA was inversely related to cognitive impulsivity and alpha-LNA was inversely related to motor and total impulsivity. These findings suggest that omega-3 fatty acid status is associated with variability in affect regulation, personality and impulse control.

Blunted hormone responses to Ipsapirone are associated with trait impulsivity in personality disorder patients.

Impulsive aggression is associated with central serotonergic dysfunction. Animal models particularly implicate the 5-HT(1A) receptor in this behavior. We tested the hypothesis that central 5-HT(1A) receptor function is impaired in impulsive aggressive personality disorder patients. A total of 52 individuals with DSM-III-R personality disorders, all medically healthy adult outpatients without concurrent psychiatric medication treatment, underwent serial plasma cortisol, prolactin, and temperature measurements before and after ipsapirone 20 mg oral administration. Subjects completed self-report measures of impulsivity, hostility, depression and anxiety, and childhood maltreatment. Stepwise regression analysis revealed impulsivity alone among symptom measures to be associated with significantly decreased peak cortisol and prolactin responses. Diagnoses of borderline personality disorder (BPD) and intermittent explosive disorder-revised (IED-R) were associated with significantly increased and decreased cortisol responses, respectively. However, post hoc analyses indicated that impulsivity was significantly negatively correlated with cortisol responses in the BPD group, and may mediate the association of both BPD and IED-R with altered cortisol responses. Temperature response was associated with neither diagnostic nor symptom measures. Neither diagnostic nor dimensional measures of depression or anxiety, nor severity of childhood maltreatment, were significantly associated with cortisol, prolactin, or temperature responses. Impulsivity is related to impaired function at (or downstream to) postsynaptic 5-HT(1A) receptors, and this relationship may be partly responsible for the association of impaired serotonergic function with diagnoses such as BPD and IED-R. In addition, D(2) receptor dysfunction may play a role in impulsivity, whereas 5-HT(1A) cell-body autoreceptor function may be spared in these disorders.

Cognition and motor control as a function of Delta9-THC concentration in serum and oral fluid: limits of impairment.

Cannabis use has been associated with increased risk of becoming involved in traffic accidents; however, the relation between THC concentration and driver impairment is relatively obscure. The present study was designed to define performance impairment as a function of THC in serum and oral fluid in order to provide a scientific framework to the development of per se limits for driving under the influence of cannabis. Twenty recreational users of cannabis participated in a double-blind, placebo-controlled, three-way cross-over study. Subjects were administered single doses of 0, 250 and 500 microg/kg THC by smoking. Performance tests measuring skills related to driving were conducted at regular intervals between 15 min and 6h post smoking and included measures of perceptual-motor control (Critical tracking task), motor impulsivity (Stop signal task) and cognitive function (Tower of London). Blood and oral fluid were collected throughout testing. Results showed a strong and linear relation between THC in serum and oral fluid. Linear relations between magnitude of performance impairment and THC in oral fluid and serum, however, were low. A more promising way to define threshold levels of impairment was found by comparing the proportion of observations showing impairment or no impairment as a function of THC concentration. The proportion of observations showing impairment progressively increased as a function of serum THC in every task. Binomial tests showed an initial and significant shift toward impairment in the Critical tracking task for serum THC concentrations between 2 and 5 ng/ml. At concentrations between 5 and 10 ng/ml approximately 75-90% of the observations were indicative of significant impairment in every performance test. At THC concentrations >30 ng/ml the proportion of observations indicative of significant impairment increased to a full 100% in every performance tests. It is concluded that serum THC concentrations between 2 and 5 ng/ml establish the lower and upper range of a THC limit for impairment.

Impulsive-aggressive traits, serotonin function, and alcohol-enhanced aggression.

Although alcohol consumption is involved in most acts of violence, most people do not become violent when they drink. Individuals also respond differently to alcohol on laboratory measures of aggression. The objective of this study was to determine whether individual differences in the effects of alcohol on a laboratory measure of aggression are related to specific personality traits and/or serotonin function, as measured by prolactin response to pharmacochallenge. Psychometric scales for impulsiveness, aggression, and anger, as well as a probe for suspiciousness, were administered to 10 healthy male social drinkers. Trait serotonin function was determined by citalopram challenge. The effect of alcohol on the Point Subtraction Aggression Paradigm was determined by comparing aggression scores with and without 1 g/kg alcohol. Impulsivity scores were significantly correlated with the change in aggressive responding after alcohol. Aggression, anger, and suspiciousness scores were not. Prolactin response did not predict the effect of alcohol on aggressive responding. The results suggest that trait impulsiveness may mediate the effects of alcohol on aggression in normal males.

Psychobiological concomitants of history of suicide attempts among violent offenders and impulsive fire setters.

Psychobiological data on 58 violent offenders and impulsive fire setters were analyzed for associations with history of suicide attempts. Subjects with a history of suicide attempts serious enough to require an admission to a medical facility had significantly lower mean cerebrospinal fluid 5-hydroxyindoleacetic acid and 3-methoxy-4-hydroxyphenylglycol concentrations than subjects who had not made such attempts. A linear discriminant function analysis based on psychobiological and behavioral variables correctly classified 79% of the subjects according to the suicide attempt history positive and negative outcomes.

Fluoxetine and impulsive aggressive behavior in personality-disordered subjects.

BACKGROUND: Evidence of an inverse relationship between central serotonergic (serotonin [5-hydroxytryptamine]) system function and impulsive aggressive behavior has been accumulating for more than 2 decades. If so, pharmacological enhancement of serotonin activity should be expected to reduce impulsive aggressive behavior in subjects in whom this behavior is prominent. METHODS: A double-blind, placebo-controlled trial of the selective serotonin-uptake inhibitor fluoxetine hydrochloride was conducted in 40 nonmajor-depressed, nonbipolar or schizophrenic, DSM-III-R personality-disordered individuals with current histories of impulsive aggressive behavior and irritability. Measures included the Overt Aggression Scale-Modified for Outpatients, Clinical Global Impression Rating of Improvement, and several secondary measures of aggression, depression, and anxiety. RESULTS: Fluoxetine, but not placebo, treatment resulted in a sustained reduction in scores on the Irritability and Aggression subscales of the Overt Aggression Scale-Modified for Outpatients that was first apparent during months 2 and 3 of treatment, respectively. Fluoxetine was superior to placebo in the proportion of "responders" on the Clinical Global Impression Rating of Improvement: first at the end of month 1, and then finally demonstrating a sustained drug-placebo difference from the end of month 2 through the end of month 3 of treatment. These results were not influenced by secondary measures of depression, anxiety, or alcohol use. CONCLUSION: Fluoxetine treatment has an antiaggressive effect on impulsive aggressive individuals with DSM-III-R personality disorder.

Relationship of psychobiological variables to recidivism in violent offenders and impulsive fire setters. A follow-up study.

Fifty-eight violent offenders and impulsive fire setters were followed up for an average of 3 years after release from prison. Recidivists who committed a new violent offense or arson had significantly lower cerebrospinal fluid 5-hydroxyindoleacetic acid and homovanillic acid concentrations and blood glucose nadirs after oral glucose challenge than did nonrecidivists. A discriminant analysis, based on the blood glucose nadir and cerebrospinal fluid 5-hydroxyindoleacetic acid concentration, correctly classified 84.2% of the subjects.

Impulsive aggression in personality disorder correlates with tritiated paroxetine binding in the platelet.

BACKGROUND: To examine the relationship between binding parameters of the platelet central serotonergic (5-HT) transporter and measures of aggression and impulsivity in adult human subjects. METHODS: Maximal number of platelet tritiated paroxetine binding sites (Bmax) and dissociation constant (Kd) values were measured in patients with personality disorder (n = 24) and healthy volunteers (n = 12). Measures of aggression and impulsivity included the total score and aggression subscale of the Life History of Aggression, the Motor Aggression factor and the assault subscale of the Buss-Durkee Hostility Inventory, and the total score and motor impulsivity subscale of the Barratt Impulsiveness Scale. RESULTS: The Bmax, but not Kd, values of platelet tritiated paroxetine binding was inversely correlated with the Life History of Aggression total score and aggression score and with the Buss-Durkee Hostility Inventory assault score in patients with personality disorder but not in healthy volunteer subjects. This relationship was independent of influences of factors related to depression, global function, or history of alcoholism or drug abuse. CONCLUSIONS: Reduced numbers of platelet 5-HT transporter sites may covary with life history of aggressive behavior in patients with personality disorder. This may represent another abnormality in 5-HT function in individuals with personality disorder and aggressive behavior.

Plasma phospholipid essential fatty acids and prostaglandins in alcoholic, habitually violent, and impulsive offenders.

Plasma phospholipid essential fatty acids and some of their main metabolites, prostaglandins, were measured among habitually violent and impulsive male offenders, who all had alcohol abuse problems, and nonviolent control persons. Linoleic acid (18:2n-6), the precursor of the n-6 fatty acids, was below normal in intermittent explosive disorder, but the dihomogammalinolenic acid (DGLA) (20:3n-6) and some subsequent n-6 acids were at the same time elevated among all offenders. Also, a monounsaturate, oleic acid (18:1n-9) was elevated. The high DGLA correlated with low cholesterol level in intermittent explosive disorder. The arachidonic acid metabolites PGE2 and TxB2 were elevated in violent antisocial personality. The PGE1/DGLA ratio was low in intermittent explosive disorder. The number of registered violent crimes and violent suicidal attempts correlated with high phospholipid DGLA values. The possibility that the high phospholipid DGLA is connected with low free DGLA pool, and therefore low PGE1 formation, among these offenders is discussed.

Serum cholesterol, suicidal tendencies, impulsivity, aggression, and depression in adolescent psychiatric inpatients.

BACKGROUND: This study was undertaken to examine the relationship between serum cholesterol levels and suicidal behaviors in adolescent psychiatric inpatients. Any association between serum cholesterol and measures of suicidal behavior, impulsivity, aggression, anxiety, and depression was also examined. METHODS: Consecutive admissions (n = 152) to an adolescent psychiatric inpatient unit were assessed using measures of suicidal behavior, violence, impulsivity, and depression. Serum cholesterol was compared between those admitted for reasons of suicidal tendencies and those for other reasons. Correlation between serum cholesterol and measures of suicidal behavior, violence, impulsivity, and depression were examined. RESULTS: Serum cholesterol levels were significantly higher in adolescent patients who were currently suicidal than in nonsuicidal adolescents. Within the suicidal group, but not in the total inpatient group, serum cholesterol correlated negatively with the degree of suicidal behavior. No correlation between serum cholesterol levels and depression, violence, and impulsivity were detected. No significant differences were found in serum cholesterol levels between diagnoses or between suicidal and nonsuicidal patients within each diagnostic group. CONCLUSIONS: The association between cholesterol and suicidal tendencies remains complex and may depend on several variables within the population studied. Its usefulness as a biologic risk factor in clinical samples remains to be determined.

Borderline personality, impulsiveness, and platelet monoamine measures in bulimia nervosa and recurrent suicidal behavior.

This study examined the relationship between borderline and impulsive personality traits on the one hand, and monoamine function on the other in 15 women with bulimia nervosa and 15 women with recurrent suicidal behavior. Platelet serotonin (5-HT) and platelet monoamine oxidase (MAO) activity were used as peripheral measures of monoaminergic function. All suicide attempters were diagnosed as having a borderline personality disorder, whereas this diagnosis was less frequent in bulimics. Bulimics with borderline comorbidity resembled recurrent suicide attempters with borderline personality disorder more closely in both psychological (anger, impulsive behavior) and biochemical characteristics (platelet 5-HT) than bulimics without borderline personality disorder. Platelet 5-HT was higher in patients with borderline personality than in normal female controls and was positively correlated with the disposition to experience anger. Impulsive personality traits were consistently negatively correlated with platelet MAO activity. Our findings support the subdivision of bulimics according to the presence of borderline or "multi-impulsive" personality disorder.

Impulsivity, aggression, and neuroendocrine responses to serotonergic stimulation in substance abusers.

Alterations in the activity of central serotonergic systems have been implicated in impulsive and aggressive behavior. We examined the neuroendocrine and psychological responses of 24 substance users with differing levels of aggressiveness and impulsivity to the oral administration of an indirect serotonin agonist fenfluramine (60 mg) or placebo given in a double-blind crossover design. All subjects were volunteers on a closed research ward and were abstinent from drugs for a minimum of 5 days. Baseline plasma prolactin (PRL) levels were greater in the groups with higher levels of self-reported aggressiveness and impulsivity. When adjusted for the baseline, PRL and cortisol responses 180 min after fenfluramine administration were significantly elevated in subjects with higher levels of aggressiveness and impulsivity. Peak cortisol levels were correlated with impulsivity. PRL and cortisol responses to fenfluramine were more strongly correlated with impulsivity than aggressiveness. Also, the more impulsive subjects reported a decrease in subjective states of depression, hostility and anxiety after drug treatment. These data further support the hypothesis of altered serotonergic activity in aggressive and impulsive behaviors.

CSF 5-HIAA levels are lower in impulsive as compared to nonimpulsive violent suicide attempters and control subjects.

BACKGROUND: We studied CSF 5-HIAA and HVA concentrations in violent suicide attempters and examined their relationship with depression, anxiety, and impulsivity. METHODS: CSF 5-HIAA and HVA concentrations were determined very shortly after hospital admission and compared to those of a matched control population. Clinical evaluation was performed concomitantly; the level impulsivity was evaluated by the Impulsivity Rating Scale (IRS). RESULTS: Twenty-three patients and 23 control subjects were included. According to the IRS, 14 patients were classified as impulsive, including all patients suffering from personality disorders, and 9 as nonimpulsive, with a main DSM-IIIR diagnosis of melancholia. CSF 5-HIAA concentrations in the suicide group were significantly lower than in control subjects. This difference was entirely due to the impulsive suicide attempters. There was an inverse correlation between the IRS score and CSF 5-HIAA (r = -.47, p = .02) and only a trend for HVA (r = -.41, p = .078) levels in the suicide group. CONCLUSIONS: This study of a group of violent suicide attempters distinguished a subgroup of patients diagnosed with personality disorder with high impulsivity scores and a subgroup of patients with the main diagnosis of severe depression. CSF 5-HIAA was significantly lower in impulsive violent attempters than in nonimpulsive violent attempters, therefore desintangling violence from impulsivity and linking this biologic abnormality to impulsivity.