Relationship between substance abuse and first-episode psychosis - A South African perspective
Background. Co-morbidity between susbstance abuse and psychotic disorders is high. Few studies have examined the relationship between first-episode psychosis and substance abuse. Several questions emerge from this common relationship and many of them remain unanswered. Objectives. To determine the effect of substance abuse on psychosis in terms of onset, duration, severity of symptoms, use of medication and outcome. Method. Thirty-three subjects with first episode psychosis, as well as primary caregivers, were interviewed regarding substance abuse and its relation to illness. Thirty-six control subjects were also interviewed. Result. Twenty-seven per cent of subjects abused substances in the 3 months before onset of illness, and 77.8% of the abusers were male. Subjects in the first episode psychosis group were more likely to choose cannabis as their susbtance of abuse than controls. Subjects with first-episode psychosis who abused substances presented at an earlier age than non abusers. Substances affected symptoms at baseline presentation. Conclusions. Substance abuse has a significant impact on first onset psychosis as far as age of onset and symtom severity are concerned. Subjects with an underlying vulnerability to psychosis seem to start abusing susbtances at an earlier age than the general population. Males are more likely to abuse substances than females.