Richard J. Kavoussi

Assessment of life history of aggression: development and psychometric characteristics

The Life History of Aggression (LHA) assessment was administered to up to 252 subjects. In addition to a total LHA score, subscale scores for Aggression, Social Consequences and Antisocial Behavior, and Self-directed Aggression were calculated. Test-retest stability, interrater agreement, and internal consistency reliability were excellent both for the LHA Total score and the LHA Aggression subscore. There were moderately strong correlations between these scores and both self-reports of aggressive tendency (Buss-Durkee Hostility Inventory: n = 214) and recent overt aggression (Overt Aggression Scale-Modified for Out-patients: n = 61). LHA Total scores were highest among subjects with Antisocial or Borderline Personality Disorder. These results support the use of the LHA assessment, and especially the LHA Aggression subscore, as a measure of life history of aggressive behavior.

Intermittent explosive disorder-revised: Development, reliability, and validity of research criteria

The study of human aggression has been hindered by the lack of reliable and valid diagnostic categories that specifically identify individuals with clinically significant displays of impulsive aggressive behavior. DSM intermittent explosive disorder (IED) ostensibly identifies one such group of individuals. In its current form, IED suffers from significant theoretical and psychometric shortcomings that limit its use in clinical or research settings. This study was designed to develop a revised criteria set for IED and present initial evidence supporting its reliability and validity in a well characterized group of personality disordered subjects. Accordingly, research criteria for IED-Revised (IED-R) were developed. Clinical, phenomenologic, and diagnostic data from 188 personality disordered individuals were reviewed. IED-R diagnoses were assigned using a best-estimate process. The reliability and construct validity of IED-R were examined. IED-R diagnoses had high interrater reliability (kappa = .92). Subjects meeting IED-R criteria had higher scores on dimensional measures of aggression and impulsivity, and had lower global functioning scores than non-IED-R subjects, even when related variables were controlled. IED-R criteria were more sensitive than DSM-IV IED criteria in identifying subjects with significant impulsive-aggressive behavior by a factor of four. We conclude that in personality disordered subjects, IED-R criteria can be reliably applied and appear to have sufficient validity to warrant further evaluation in field trials and in phenomenologic, epidemiologic, biologic, and treatment-outcome research.

Relationship of prolactin response to d-fenfluramine to behavioral and questionnaire assessments of aggression in personality-disordered men

Prolactin (PRL) responses to acute challenge with the serotonin (5-HT) releaser/uptake inhibitor, d-fenfluramine (PRL[d-FEN]), were correlated with three different measures of aggression in 14 male personality-disordered subjects. Consistent with previous work, PRL[d-FEN] responses were inversely correlated with scores on the Buss-Durkee Hostility Inventory-Assault scale (BDHI-Assault) and with the Brown-Goodwin Aggression-Revised (BGA-R) Aggression scale. In addition, PRL[d-FEN] responses were inversely correlated with a direct laboratory measure of aggressive behavior (Point-Subtraction Aggression Paradigm: PSAP). Although all measures of aggression correlated with PRL[d-FEN] response, differences among the intercorrelations of these measures were found. Specifically, BGA-R Aggression scores correlated with both BDHI-Assault and PSAP scores, but no relation was found between BDHI-Assault and PSAP scores. The results suggest that central 5-HT function may be associated with both self-report and behavioral measures of aggressive behavior, which may represent somewhat separate aspects of aggressive behavior.

A double-blind, randomized, placebo-controlled trial of fluoxetine in patients with intermittent explosive disorder.

BACKGROUND Intermittent explosive disorder (IED) is a disorder of impulsive aggression that affects as many as 7.3% of the U.S. population during some period of life. Since central serotonergic (5-HT) system dysfunction is related to impulsive aggressive behavior, pharmacologic enhancement of 5-HT activity should reduce impulsive aggressive behavior in individuals with IED. METHOD A double-blind, randomized, placebo-controlled trial of the selective 5-HT uptake inhibitor fluoxetine was conducted in 100 individuals with IED (research diagnostic criteria) and current histories of impulsive aggressive behavior. The primary efficacy measure was the aggression score from the Overt Aggression Scale-Modified (OAS-M) for Outpatient Use. Secondary efficacy measures included the irritability score from the OAS-M and the Clinical Global Impressions-Improvement scale (CGI-I) score. The study took place between July 1990 and July 1999. RESULTS Fluoxetine treatment resulted in a sustained reduction in OAS-M aggression, and OAS-M irritability scores, apparent as early as week 2 (p < .01 for aggression and p < .001 for irritability at endpoint). Fluoxetine was also superior to placebo in the proportion of responders on the CGI-I (p < .001). Closer examination of the data revealed that full or partial remission of impulsive aggressive behaviors, as reflected by the A criteria for IED, occurred in 46% of fluoxetine-treated subjects. Fluoxetine did not exert an antidepressant or antianxiety effect, and its effects on impulsive aggression were not influenced by presence of current symptoms of depression or anxiety. CONCLUSION Fluoxetine treatment has a clear antiaggressive effect in impulsive aggressive individuals with IED. However, while fluoxetines antiaggressive effects appear robust, they lead to full or partial remission of IED in less than 50% of subjects treated with fluoxetine.

Long-term efficacy of pregabalin in generalized anxiety disorder.

A multicenter, randomized, placebo-controlled, double-blind study was conducted to evaluate the efficacy of pregabalin in preventing relapse of generalized anxiety disorder (GAD) after response to short-term treatment. Outpatients (n=624) with GAD for ≥1 year received open-label pregabalin (450 mg/day) for 8 weeks and, if a clinical response was observed, were randomized to receive either pregabalin (450 mg/day; n=168) or placebo (n=170) for 24 weeks. The primary efficacy parameter was time to relapse. Among responders to open-label acute treatment with pregabalin, time to relapse of GAD was significantly longer for patients treated with pregabalin compared with placebo (P<0.0001). Fifty per cent of the placebo group had relapsed by day 23, and at study endpoint, 65% had relapsed. In the pregabalin group, only 42% had relapsed by study end. Total attrition during double-blind treatment was somewhat higher on pregabalin compared with placebo (21.4 vs. 15.3%); attrition owing to adverse events (AEs) was also somewhat higher on pregabalin (6.0 vs. 2.4%). AEs were relatively low in the double-blind phase; only three AEs occurred with an incidence of more than 5% on pregabalin and placebo, respectively: infection (14.9 vs. 11.2%), headache (10.1 vs. 11.2%), and somnolence (6.0 vs. 0%). No safety concerns were identified with long-term treatment. The study indicates that pregabalin is an effective treatment for the prevention of relapse in patients with GAD.

Impulsive aggression in personality disorder correlates with platelet 5-HT2A receptor binding

The purpose of this study was to examine the relationship between platelet 5-HT2A receptor binding and aggressive behavior. 125I-LSD Bmax and Kd values were measured for 22 subjects meeting DMS-III-R criteria for one or more personality disorders and 12 healthy volunteer subjects. Aggression and impulsivity were assessed using the Buss-Durkee Hostility Inventory (BDHI) Assault scale, Life History of Aggression (LHA) scale, and the Barratt-11 Impulsiveness scale (BIS-11). Bmax and Kd values did not differ between personality disordered subjects and healthy volunteers. However, both Bmax and Kd values correlated positively with BDHI Assault scores in personality-disordered subjects but not in healthy volunteer subjects. These results suggest that assaultiveness in personality-disordered subjects may covary with increasing numbers, but decreasing affinity, of platelet 5-HT2A receptor sites labeled by 125I-LSD.

Physiological responses to d-fenfluramine and ipsapirone challenge correlate with indices of aggression in males with personality disorder

Hormonal responses to challenge with the 5-HT2A/2C probe d-fenfluramine and hormonal and thermal responses to challenge with the 5-HT1A probe ipsapirone were correlated with self-report and historical assessments of aggression in a pilot sample of eight male personality-disordered individuals. Prolactin responses to d-fenfluramine and cortisol responses to ipsapirone challenge were inversely correlated with self-reported assaultiveness. Thermal responses to ipsapirone were inversely correlated with a historical assessment of aggression. Since none of these physiological indices of 5-HT system function were intercorrelated, it is possible that simultaneous assessment of these 5-HT indices may yield a more comprehensive assessment of the relationship between central 5-HT system function and aggressive behavior in humans.

5-HT2a/2c receptor blockade by amesergide fully attenuates prolactin response tod-fenfluramine challenge in physically healthy human subjects

Prolactin responses tod-fenfluramine (d-FEN) challenge (0.5 mg/kg PO) were examined after pre-treatment with and without the 5-HT2a/2c receptor antagonist amesergide in eight physically healthy male volunteers. Compared to pretreatment with placebo, pre-treatment with amesergide completely blocked the prolactin (PRL) response tod-FEN challenge in all subjects. These data are consistent with data demonstrating a complete blockade of the PRL response tod-FEN with the 5-HT2a/2c receptor antagonist ritanserin, and suggest that the PRL response tod-FEN challenge in humans may largely be due to activation of the 5-HT2a/2c receptor.

Aggression, Suicidality, and Intermittent Explosive Disorder: Serotonergic Correlates in Personality Disorder and Healthy Control Subjects

Central serotonergic (5-HT) activity has long been implicated in the regulation of impulsive aggressive behavior. This study was performed to use a highly selective agent for 5-HT (d-Fenfluramine, d-FEN) in a large group of human subjects to further explore this relationship dimensionally and categorically. One hundred and fifty healthy subjects (100 with personality disorder, PD and 50 healthy volunteer controls, HV) underwent d-FEN challenge studies. Residual peak delta prolactin (ΔPRL[d-FEN]-R; ie, after the removal of potentially confounding variables) was used as the primary 5-HT response variable. Composite measures of aggression and impulsivity were used as dimensional measures, and history of suicidal/self-injurious behavior as well as the presence of intermittent explosive disorder (IED) were used as categorical variables. ΔPRL[d-FEN]-R responses correlated inversely with composite aggression, but not composite impulsivity, in all subjects and in males and females examined separately. The correlation with composite aggression was strongest in male PD subjects. ΔPRL[d-FEN]-R values were reduced in PD subjects with a history of suicidal behavior but not, self-injurious behavior. ΔPRL[d-FEN]-R values were also reduced in patients meeting Research Criteria for IED. Physiologic responses to 5-HT stimulation are reduced as a function of aggression (but not generalized impulsivity) in human subjects. The same is true for personality disordered subjects with a history of suicidal, but not self-injurious, behavior and for subjects with a diagnosis of IED by research criteria. These data have particular relevance to the notion of impulsive aggression and the biological validity of IED.

Hormonal responses to d- and d,l-fenfluramine in healthy human subjects

Two different doses of d-fenfluramine HCl and d,l-fenfluramine HCl (0.5 mg/kg and 1.0 mg/kg) were administered to 11 healthy male volunteers to compare the neuroendocrine responses to these two forms of fenfluramine in human subjects. Prolactin (PRL) responses to d- and d,l-fenfluramine were significantly greater than those to placebo and were equivalent at both dose levels. Adrenocortiatrophic-releasing hormone (ACTH) and cortisol (CORT) responses to d-fenfluramine at both dose levels were also significantly greater than those to placebo. In contrast, the higher dose of d,l-fenfluramine was associated only with a significant CORT response in comparison to placebo. PRL responses to d-fenfluramine were higher than the PRL response to d,l-fenfluramine at either dose level. The PRL response to d-fenfluramine at 0.5 mg/kg was very highly correlated with the PRL responses to d,l-fenfluramine at 1.0 mg/kg (r = 0.97, n = 10). Homovanillic acid (HVA) were not altered by either d, or d,l-fenfluramine at either dose in a subsample of subjects (n = 4). ACTH/CORT responses to d- and d,l-fenfluramine were modestly intercorrelated. These data suggest that the PRL response evoked by d-fenfluramine is quantitatively very similar to that evoked by d,l-fenfluramine.