Grant: CIHR Clinician Scientist - Phase 1

Human aggression and violence represent significant public health concerns in Canada and worldwide. The World Health Organization provided a one-year, worldwide estimate of 1.43 million deaths due to self-inflicted or interpersonal violence (excluding armed conflict), with most fatalities resulting from unplanned or impulsive acts of aggression (WHO, 2007). Borderline personality disorder (BPD), which affects 2% of the population, and antisocial personality disorder (ASPD), found in 6.5% of Canadian males, are two common psychiatric conditions often seen in people who act aggressively on impulse. These individuals undermine the health of the population through their repeated acts of aggression toward themselves and others. Certain animals lacking a brain chemical called monoamine oxidase A (MAO-A) act very aggressively compared with animals that have normal brain levels of MAO-A. MAO-A is a brain protein that affects brain development. Levels of MAO-A are low in healthy people who report more impulsive behavior. At present, we do not know whether MAO-A is low in people who are extremely impulsive and aggressive and have BPD or ASPD. We propose using a well-developed brain scanning technique called [11C] harmine positron emission tomography (PET) to study MAO-A levels in the brains of aggressive and impulsive people with ASPD or BPD. We will also use [11C] harmine PET to study brain MAO-A levels in healthy people without personality disorders who do not act aggressively. We hypothesize that brain MAO-A levels will be lower in people with ASPD or BPD compared with healthy people. Our anticipated results could have important implications for the prevention and treatment of maladaptive aggression and impulsivity. For example, lower brain MAO-A in aggressive people with BPD or ASPD may mean that treatments which raise MAO-A or perform the same function as MAO-A could lower impulsivity, aggression, and violence.