The substance use among forensic psychiatric patients.

OBJECTIVES

The primary goal of this study was to examine the relative differences in the use of illegal substances (i.e., amphetamine, cannabis, opiates) among forensic patients who have committed a violent crime compared with the general population. The aim was also to find out if there were differences in substance use among forensic versus nonforensic patients with psychosis diagnosis.

METHODS

The study population consisted of 190 persons, who were involuntarily ordered to hospital treatment as forensic patients in Finland. The information was compared with data from the national hospital discharge register. These results were also compared with national statistics from the general population.

RESULTS

Among forensic patients, the lifetime prevalence of cannabis use was 2-fold, amphetamine use 40-fold, and opiate use over 60-fold higher than estimated from the general population in Finland. Cannabis use was 1.5-fold more common than amphetamine use among forensic patients and 1.3-fold more common among nonforensic patients. The prevalences of cannabis-related diagnoses were 4.7- and 3.7-fold more common than opiate use among forensic and nonforensic patients, respectively.

CONCLUSIONS

Cannabis, amphetamine, and opiate use are associated with an increased risk of becoming a forensic psychiatric patient, but no substantial differences were observed among patients with psychosis diagnosis in the relative risk increase for cannabis versus amphetamine versus opiate use, indicating that none of these drugs are uniquely associated with violent offending among mentally ill.