Lifetime Cannabis Use Disorder Is Not Associated With Lifetime Impulsive Behavior and Severe Violence in Patients...

The link between substances of abuse, impulsivity, and violence in psychotic patients remains unclear. This study aims at unraveling whether cannabis use disorder is associated with violent and/or psychotic behavior in patients who are hospitalized in a high-security hospital.

We conducted a cross-sectional retrospective study in 124 patients with schizophrenia spectrum disorders admitted to a high-security hospital. Lifetime violent behavior was assessed using the History of Aggressive Behavior Form-Subject of the MacArthur Violence Risk Assessment Study and impulsivity using the Psychopathy Checklist-Revised (considering items: "proneness to boredom," "lack of self-control," and "impulsive thoughtless gestures"). Substance use disorder was diagnosed according to Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition criteria. Positive and Negative Syndrome Scale was also administered.

Violent and nonviolent psychotic patients showed similar prevalence of cannabis use disorder. Alcohol and cocaine use disorders were more prevalent among violent psychotic patients. Cannabis use disorder was not associated with any dimension of impulsivity, whereas alcohol use disorder was positively correlated to impulsive thoughtless gestures (standardized β = 0.213, P = 0.027) and cocaine use disorder with proneness to boredom (standardized β = 0.290, P = 0.002). Finally, logistic regression analysis revealed that, unlike cannabis and cocaine use disorders, alcohol use disorder (odds ratio, 3.964; 95% confidence interval, 1.729-9.087; P = 0.001) was a factor associated with violence.

These findings show that cannabis and alcohol are largely abused and coabused by psychotic patients with a propsensity for violence, but only alcohol is associated with impulsive and violent behavior. Therefore, especially alcohol abuse should be seriously considered by practitioners when evaluating the dangerousness of patients with schizophrenia spectrum disorders.