Predictors of psychosis severity in individuals with primary stimulant addictions

The goal of this study is to define the factors that could contribute to the development, severity, and persistence of psychotic symptoms in individuals with stimulant addiction. We hypothesize that particular drug use variables may contribute to the severity of psychiatric symptoms. Thirty-seven stimulant users, abstinent for >30 days were recruited from the community. Previous drug use and current and past psychiatric symptoms were assessed using validated objective rating scales and several self-report questionnaires. Age at first use of the stimulant drug was inversely related to the Beck Anxiety Inventory score, and the subjects with more than 5 years duration of chronic use exhibited greater severity of symptoms on the PANSS Positive and General Scales and total score. The method of drug administration, duration of abstinence, latency from first use to regular use, and prior solicitation of treatment were not related to PANSS total and subscale scores or other clinical variables. Severity of psychosis appears to be related to earlier and longer exposure to stimulants, consistent with a "threshold" effect of stimulant use on the development of psychotic symptoms. The association may also suggest a critical developmental period that is most susceptible to the deleterious effects of stimulant exposure.