Animal and human studies suggest that aggressive behavior may be modulated by brain serotonergic system. Serotonergic (5-HT) dysfunction is associated with post-traumatic stress disorder (PTSD), but also with increased aggression and impulsivity, hallmarks of PTSD. The aim of the study was to investigate the association of platelet 5-HT concentration and various types of aggression and impulsivity in veterans with PTSD. A group of 42 male combat-related PTSD subjects entered the study. Four different aggression facets were measured by the Buss and Perry's Aggression Questionnaire (BPAQ). Verbal and physical types of impulsive aggressive behavior were measured by the subscales of the Žužul's Aggressiveness Inventory A-87. Impulsivity was determined using Eysenck's IVE questionnaire. PTSD severity was evaluated by Watson's PTSD questionnaire. Platelet serotonin concentration was determined spectrofluorimetrically. Confounding variables were: age, body mass, alcohol use, comorbid depression, and tobacco use. Platelet 5-HT concentration and PTSD severity were independently associated only with impulsive types of aggression, as higher platelet 5-HT concentration and more severe PTSD were related to more impulsive aggression. These results strongly recommend distinguishing between specific types of aggression facets, and advise the importance of theory-based concepts of aggression facets when evaluating the biological correlates of aggression.
Keywords: Aggression; depression; impulsivity; platelet serotonin; post-traumatic stress disorder; veterans.