Imbalance between nitric oxide and dopamine may underly aggression in acute neurological patients.

The neurochemical basis of aggressive behavior in humans is not fully understood. In this study we explored the relationship between aggressiveness (as measured by the Overt Aggression Scale), cognitive performance (as measured by the Mini Mental State Examination), and biochemical markers of dopamine neurotransmission (homovanillic acid, HVA) and nitric oxide synthesis (nitrite plus nitrate, NO(x)) in cerebrospinal fluid from 70 patients with acute brain disorders, mainly brain infections. Aggressive behavior and cognitive performance showed an inverse correlation. NO(x)/HVA ratio was inversely correlated to aggressive behavior, and positively correlated to cognitive performance. A subanalysis with antipsychotic-naïve patients confirmed those results. The balance between nitric oxide and dopamine could be related to the cognitive control of aggressive impulse.