Aggression, Impulsivity and Serotonin in Drug Dependence

Terry Jean Allen, The University of Texas Graduate School of Biomedical Sciences at Houston


Aggression, impulsivity, and central serotonergic function were evaluated in two groups of human volunteers; one group having a history of substance dependence (DRUG+) and another group with no drug use history (DRUG-). The hypothesis was that DRUG+ subjects would be more aggressive, more impulsive, and have attenuated serotonergic function. Results showed that DRUG+ subjects behaved more aggressively in a computer paradigm of aggression and also reported more aggression on questionnaires than DRUG- subjects. In a computer paradigm of impulsivity, the DRUG+ group showed a lesser ability to delay gratification than the DRUG- group in the last session of testing. The DRUG+ subjects also reported more venturesomeness and problems associated with low impulse control on questionnaires. Serotonergic function was measured through the neuroendocrine and hypothermic response to an orally administered serotonin (5-HT) agonist specific to the 5-HT1A receptor subtype (ipsapirone). The neuroendocrine responses did not differ between DRUG± groups, indicating no difference in the sensitivity of the presynaptic or postsynaptic 5-HT1A receptors. An unexpected result was that the indicator hormone, cortisol, was at a lower baseline level in the DRUG+ group than the DRUG- group. Lowered cortisol levels have been previously noted in children at high risk foul antisociality and future drug use. A principal components analysis including impulsivity, aggression, and serotonergic function measures produced three unique factors. The factors, Antisocial Tendency and Self-Control and Serotonergic Function combined to produce a significant regression equation explaining 36% of variability in the DRUG± groups. These factors included measures of aggression, impulsivity, mood, and educational attainment. These results suggest that the current measures of aggression and impulsivity were predictive of a drug dependence disorder but that neuroendocrine function is not yet a useful indicator of drug dependence status.

Subject Area

Neurosciences|Experimental psychology|Physiological psychology|Psychology

Recommended Citation

Allen, Terry Jean, "Aggression, Impulsivity and Serotonin in Drug Dependence" (1996). Texas Medical Center Dissertations (via ProQuest). AAI9626085.