Aggressiveness is associated with excitement on the five-factor model of the positive and negative syndrome scale and prefrontal function in patients with stable schizophrenia.

Aggressiveness is a clinical concern in the stable phase of schizophrenia, as well as in the acute phase. The factors that affect aggressiveness during the stable phase remain unclear. This study investigated factors associated with aggressiveness in patients with stable schizophrenia. Sixty-six patients with schizophrenia who were in the stable phase without acute exacerbation were assessed for aggressiveness using the Buss-Perry Aggression Questionnaire; impulsivity using the Barratt Impulsiveness Scale Version 11, psychotic symptoms using the five-factor model of the Positive and Negative Syndrome Scale (PANSS) including positive symptoms, negative symptoms, disorganization, excitement, and emotional distress; and prefrontal hemodynamic responses using near-infrared spectroscopy. Multivariate regression analyses showed that the excitement factor of the PANSS five-factor model, which comprised four PANSS items (poor impulse control, hyperactivity, hostility, and uncooperativeness), and delayed prefrontal hemodynamic responses were associated with elevated aggressiveness. These findings suggest that in patients with stable schizophrenia, excitement symptoms and prefrontal dysfunction are associated with elevated aggressiveness. Furthermore, the impact of impulsive traits on aggressiveness is less relevant. Our results shed light on a specific aspect of aggressiveness in patients with stable schizophrenia and may indicate factors to consider in the clinical setting.