Frontal EEG response to threat, aggressive traits and a family history of alcoholism: a preliminary study

Family history of alcoholism mediates the frontal response to alcoholic drink odors and alcohol in at-risk drinkers

Although a family history of alcoholism is the strongest risk factor for developing alcohol dependence, there are few studies of the association between familial alcoholism and the human brain's reward system activity. We used functional magnetic resonance imaging (fMRI) to determine how family history affects the brain's response to subjects' preferred alcoholic drink odors (AO) as compared to appetitive control odors (ApCO). Fourteen non-dependent heavy drinkers (HD) who were family history positive (FHP) participated, as did 12 HD who were family history negative (FHN). Subjects were imaged under both alcohol intoxication and placebo, using intravenous infusion and pharmacokinetic modeling to target a blood alcohol level of 50 mg%. Under placebo, HD-FHP had a larger medial frontal [AO>ApCO] effect than did HD-FHN. Alcohol intoxication dampened this response in the HD-FHP but potentiated it in the HD-FHN. This suggests that a family history of alcoholism and brain exposure to alcohol interact in heavy drinkers to differentially affect how the brain responds to alcohol cues.

Electrophysiological substrates of impulsiveness: potential effects on aggressive behavior

Previous investigations attempting to examine impulsiveness as a personality construct are likely confounded with a high incidence of aggressive and antisocial behavior. The present study assessed electroencephalographic activity at rest and during photic stimulation in two groups: (1) an impulsive group (n=10) scoring high on the Barratt Impulsiveness Scale (BIS-11) and reporting no indication of impulsive aggressive behavior; and (2) a non-aggressive control group (n=14) scoring within the normal range on the BIS-11. All subjects completed a brief battery of personality measures related to impulsivity and aggression. Resting EEG was recorded at 9 electrode sites. Photic stimulation was administered at three frequency levels. The primary findings were consistently lower frontal delta and theta activity in the impulsive group as well as a different topographical pattern of beta activity between the groups. These differences appeared to be independent of photic stimulation. Personality analyses indicated significantly greater hostility and lifetime history of aggression in the impulsive group. Taken together, the personality and EEG results suggest some similarity between the present impulsive group and research on groups regularly exhibiting premeditated aggression. These results provide unique insight into the construct of impulsivity and its role in the expression of specific subtypes of aggressive behavior.

Genetic influences on the association between personality risk factors and alcohol use and abuse

The authors assessed the association of 2 personality dimensions with use and abuse of alcohol in 1,320 twin pairs concordantly reporting nonabstinence at age 18.5 years. The 2 alcohol outcomes differentially relate to the 2 personality dimensions: Alcohol-related problems correlate more highly with social deviance than with excitement seeking (ES), and alcohol consumption correlates more highly with ES than with social deviance. Biometric models fit to the data identified similar patterns in genetic covariance, although differences were more evident in genetic correlations between social deviance and alcohol outcomes than in those for ES. Results suggest that genetic influences underlie the association of personality with alcohol use and subsequent problems and illustrate the utility of informative twin analyses in exploring links between genes, personality, and behavior disorder.

Neuropsychiatry of frontal lobe dysfunction in violent and criminal behaviour: a critical review

OBJECTIVES

To establish the link between frontal lobe dysfunction and violent and criminal behaviour, based on a review of relevant literature.

METHODS

Articles relating evidence of frontal lobe dysfunction with violence or crime were collected through a MEDLINE search using the keyword "frontal lobe" combined with the terms "aggression," "violence," "crime," "antisocial personality disorder," "psychopathy," "impulse control disorders", and "episodic dyscontrol." Reference lists were then searched for additional articles.

RESULTS

High rates of neuropsychiatric abnormalities reported in persons with violent and criminal behaviour suggest an association between aggressive dyscontrol and brain injury, especially involving the frontal lobes. The studies reviewed support an association between frontal lobe dysfunction and increased aggressive and antisocial behaviour. Focal orbitofrontal injury is specifically associated with increased aggression. Deficits in frontal executive function may increase the likelihood of future aggression, but no study has reliably demonstrated a characteristic pattern of frontal network dysfunction predictive of violent crime.

CONCLUSIONS

Clinically significant focal frontal lobe dysfunction is associated with aggressive dyscontrol, but the increased risk of violence seems less than is widely presumed. Evidence is strongest for an association between focal prefrontal damage and an impulsive subtype of aggressive behaviour.

The effects of familial risk, personality, and expectancies on alcohol use and abuse

This study tested a structural model of the association between familial risk, personality risk, alcohol expectancies, and alcohol abuse in a sample of 224 young adult offspring of alcoholics and 209 offspring of nonalcoholics. The results provided support for 2 personality-risk pathways, a social deviance proneness and an excitement/pleasure seeking path, that accounted for a significant portion of the association between a familial alcoholism and alcohol abuse. The path from familial alcoholism to social deviance proneness lead directly to alcohol problems. The path from familial alcoholism to excitement/pleasure seeking was associated with increased drinking, which, in turn, was associated with alcohol problems. Positive alcohol expectancies accounted for part of the association between excitement seeking and alcohol use. The results suggest 2 different biopsychosocial mechanisms that elevate risk for abuse in the offspring of alcoholics.