Aggressive responding in abstinent heroin addicts: neuroendocrine and personality correlates.

Objective measures of experimentally induced aggressiveness were evaluated in 20 abstinent heroin-dependent subjects, in comparison with 20 normal healthy male subjects. All the subjects were preliminarily submitted to DSM-IV interviews, Buss-Durkee Hostility Inventory (BDHI) and Minnesota Multiphasic Personality Inventory (MMPI II). During a laboratory task, the Point Subtraction Aggression Paradigm (PSAP), subjects earned monetary reinforcers with repeated button presses and were provoked by the subtraction of money, which was attributed to a fictitious other participant. Subjects could respond by ostensibly subtracting money from the fictitious subject (the aggressive response). Money-earning responses were not different in drug-free heroin addicts and controls during the first two sessions and significantly lower during the third session in heroin-dependent subjects (t=2.99, P<.01). Aggressive responses were significantly higher (F=4.9, P<.01) in heroin addicted individuals, in comparison with controls. During the experimentally induced aggressiveness, plasma adrenocorticotropic hormone (ACTH) and cortisol (CORT) concentrations increased less significantly, and norepinephrine (NE) and epinephrine (EPI) levels, together with heart rate (HR), increased more significantly in abstinent heroin-dependent subjects than in healthy subjects. PSAP aggressive responses positively correlated with catecholamine changes, BDHI "direct" and "irritability" scores, MMPI "psychopathic deviate" scores in heroin-dependent subjects and controls, and with CORT responses only in healthy subjects. No correlation was found between heroin-exposure extent (substance abuse history duration) and aggressiveness levels. The present findings suggest that heroin-dependent patients have higher outward-directed aggressiveness than healthy subjects, in relation with monoamine hyperreactivity, after long-term opiate discontinuation. Aggressiveness in heroin addicts seems to be related more to the personality traits than to drug effects. The impairment of hypothalamus-pituitary-adrenal (HPA) axis in abstinent addicted individuals could be due to a long-lasting action exerted by opiates on proopiomelanocortin (POMC) or to a premorbid psychobiological condition, in association with increased sympathetic arousal.

Hypothalamic-pituitary-adrenal axis responses to stress in subjects with 3,4-methylenedioxy-methamphetamine ('ecstasy') use history: correlation with dopamine receptor sensitivity.

Fifteen 3,4-methylenedioxymethamphetamine (MDMA, 'ecstasy') users who did not have other drug dependencies or prolonged alcohol abuse and 15 control subjects were studied. All the subjects were exposed to the same psychosocial stressor (Stroop Color-Word Interference Task, public speaking and mental arithmetic in front of an audience) 3 weeks after MDMA discontinuation. Plasma concentrations of adrenocorticotropic hormone (ACTH) and cortisol were measured immediately before the tests began and at their end, 30 min later. Growth hormone (GH) responses to the dopaminergic agonist bromocriptine and psychometric measures (Tridimensional Personality Questionnaire, Minnesota Multiphasic Personality Inventory, Buss-Durkee Hostility Inventory) were also obtained 4 weeks after MDMA discontinuation for the same subjects. ACTH and cortisol basal levels were significantly higher in ecstasy users than in control subjects. In contrast, ACTH and cortisol responses to stress were significantly blunted in MDMA users. The sensitivity of dopamine D2 receptors, reflected by GH responses to bromocriptine challenge, was reduced in MDMA users compared with controls. The responsiveness of the hypothalamic-pituitary-adrenal (HPA) axis (ACTH and cortisol delta peaks) correlated directly with GH areas under curves in response to bromocriptine, and inversely with psychometric measures of aggressiveness and novelty seeking. No correlation was found between hormonal measures and the extent of MDMA exposure. Reduced D2 receptor sensitivity, HPA basal hyperactivation and reduced responsiveness to stress may represent a complex neuroendocrine dysfunction associated with MDMA use. The present findings do not exclude the possibility that dopamine dysfunction partly predated MDMA exposure.

Neuroendocrine and behavioural responses to opioid receptor-antagonist during heroin detoxification: relationship with personality traits.

The present study investigated clinical, cardiovascular and neuroendocrine consequences of rapid opioid detoxification (ROD) in heroin-dependent individuals, affected, or not, by comorbid antisocial personality disorder (ASPD). Thirty-two patients underwent ROD and subsequent treatment with daily naltrexone: 3 days detoxification procedures were performed utilizing clonidine, baclofen, oxazepam and ketoprofene, without anaesthesia. Withdrawal symptoms, mood changes, cardiovascular indexes (heart rate, blood pressure), norepinephrine (NE), epinephrine (EPI), adrenocorticotropic hormone (ACTH) and cortisol (CORT) were evaluated during naloxone-naltrexone administration on the second day of detoxification treatment. The patients were divided into two groups following DSM-IV criteria for ASPD. Group A comprised 14 ASPD patients and group B comprised 18 patients without ASPD. Slight and transient withdrawal symptoms and mood changes were demonstrated on the second day in the whole sample of patients, in association with a significant, but moderate, elevation of heart rate, blood pressure, NE (two-fold), EPI (five-fold), ACTH (two-fold) and CORT (two-fold) plasma levels, in response to opioid receptor-antagonist administration. When evaluated separately in ASPD (group A) and non-ASPD patients (group B), significantly higher withdrawal symptoms and mood changes, heart rate, blood pressure, NE, ACTH and cortisol levels were observed in ASPD subjects. By contrast, no differences were found in EPI responses to naloxone-naltrexone administration between group A and B patients. The significant differences demonstrated in clinical and neuroendocrine responses to opioid receptor-antagonist administration, in relation to personality traits, could be due to reduced alpha-adrenergic receptor sensitivity, which was previously reported in ASPD, with a possible impairment of clonidine action. Our study suggests that a detailed diagnostic assessment before detoxification procedure may help to predict treatment outcome.