Symptoms and lifetime treatment experiences in psychotic patients with and without substance abuse

The main objective of this study was to compare symptom load and lifetime treatment experiences between psychotic patients with substance abuse problems and psychotic patients without substance abuse problems. This is a cross-sectional study of 48 patients (26 inpatients and 22 outpatients) in a clinic for early intervention in psychosis. Patients' were grouped into two categories based on whether they had a substance abuse problem or not. Twenty-one (43.8%) had a substance abuse problem and 27 (56.2%) had not. We used the Positive and Negative Symptom Scale (PANSS) scale to measure symptoms and several scales to measure substance abuse. Parametric tests (independent t-tests) were used to compare continuous variables, and chi-square tests were used to compare frequencies. Positive symptoms, negative symptoms, general psychopathology symptoms and the total score of psychotic symptoms did not differ significantly between the groups with psychosis alone and psychosis with substance abuse. The delusion subscore was significantly higher in the group with psychosis alone (t = -2.3, df = 41, P < 0.05), and the anxiety subscore was significantly higher in the group with psychosis with substance abuse (t = -2.3, df = 41, P < 0.05). There were no significant differences in the subscores for negative symptoms. The absence of differences in psychotic symptoms between the two groups with psychosis does not imply a strong relationship between psychotic symptoms and substance abuse. These results do not support the self-medication hypothesis. The higher rates of institutionalization among substance abusers may be explained by mechanisms other than exacerbations of psychotic symptoms, as there are few differences in symptoms among abusers and non-abusers.