Substance use disorders among mentally ill patients in a General Hospital in Sri Lanka: prevalence and correlates

To determine the prevalence, and demographic and clinical correlates of substance use disorders among the mentally ill.

Cross sectional analytical study. Data were collected from consecutive patients treated at a Tertiary care Psychiatry Unit, Western Province, Sri Lanka using an interview schedule administered by a senior registrar in psychiatry.

Diagnosis was based on ICD 10 criteria and the Clinician Rating Scale: Alcohol Use Scale (AUS) and the Drug Use Scale (DUS). The data were analysed using SPSS and WinPepi software programmes, utilising the chi squared, t test and median test.

Among a sample of 325 patients, 66% were male; 33% were diagnosed with depressive disorder, 30% with schizophrenia, 23% with bipolar affective disorder and 13% with other disorders. Prevalence of comorbid substance use disorders was 43% (95% CI 38 - 49%). Alcohol was the commonest type of substance used. Those who had a comorbid substance use diagnosis were more likely to be male, have a lower educational level, be unemployed and have a poorer level of social support. They were also found to have poorer treatment adherence, increased number of hospital admissions and an increased association with episodes of violence.

A significant proportion of patients were found to have a comorbid substance use diagnosis and associated complications. These findings have important implications for service provision for mentally ill patients with a comorbid substance use disorder.