Proneness to aggression and its inhibition in schizophrenia: Interconnections between personality traits, cognitive function and emotional processing.

OBJECTIVE: Research on aggression in schizophrenia has focused on narrowly defined deficits, while ignoring interconnections among these impairments which provide better explanatory power. Our goal was to investigate interrelations among impairments in important domains related to aggression: personality traits, including psychopathy and impulsivity, cognition and processing of emotions.

METHOD: 34 healthy controls, 37 high aggression (HAG) and 31 low aggression (LAG) patients with schizophrenia participated. The Barratt Impulsiveness Scale, Psychopathy Checklist, Wisconsin Card Sorting Test (WCST), and Emotion Recognition Test were administered. Psychiatric symptoms were assessed. Canonical Discriminant Analysis (CDA) was performed to determine how these measures distinguish among the groups and to identify underlying symptom profiles.

RESULTS: CDA revealed two statistically significant profiles of deficits which differentiated the groups. The first comprises impulsivity, psychopathy, and impairments in cognition and fear recognition. It indicates proneness to aggression. The second consists of WCST perseverative errors and facial affect processing impairment; it has an inverse relationship with aggression. These profiles are linked to different psychiatric symptoms in the schizophrenic patients: The first to excitement and poor impulse control; the second to blunted affect and motor retardation. HAG's manifested primarily the first; LAG's had a moderate score on the first and a high score on the second.

CONCLUSION: Proneness to aggression in schizophrenia is characterized by a multivariate confluence of impulsivity, psychopathy, cognitive difficulties and impairment in fear recognition. There exists, however, a second pattern of psychopathology that may suppress expression of aggression. These opposing patterns have important implications for integrated treatments of aggression.