Introduction

Despite the prevalent co-occurrence of aggression and substance use as reported by epidemiological studies, these behaviors are often addressed separately in scientific research. Neurobiological functioning - affected both by genes and environment - constitutes an essential link to the understanding of these problem behaviors. Functional neuroimaging is allowing us to take the first steps at non-invasively investigating the implicated neuroanatomical and neurochemical pathways. In particular, with sensitive and specific pharmacological and behavioral challenges we may be able to delineate causality between the factors that contribute to or protect against drug addiction, aggression, and other psychopathological processes.

How may drugs of abuse facilitate aggression?

A prevailing assumption is that substance use facilitates cognitive disinhibition and affective dysregulation. Enhanced emotionality coupled with a decrease in the ability to monitor and control behavior can facilitate different types of impulsive aggression.

Figure 1: A PET-FDG study at BNL found significant reductions (25%) in absolute measures of regional brain glucose metabolism after acute alcohol administration. However, after normalization to obtain relative regional metabolic measures, alcohol showed a relative increase of glucose metabolism in the basal ganglia and temporal cortex. Wang et al: Regional brain metabolism during alcohol intoxication. Alcoholism: Clinical and Experimental Research 2000; 24(6):822-9

The multifactorial nature of problem behaviors

Individuals showing the metabolic pattern in Figure 1 do not invariably exhibit aggressive behavior. Other factors play a role: