Background: It is a well known fact that majority of patients with schizophrenia use substances. Interrelationship between schizophrenia and substance use is complex & multifactorial. Patients with both schizophrenia & substance abuse pose a major clinical challenge to mental health professionals as it is associated with higher frequency of relapse. Aims: To identify the pattern of substance use in patients with schizophrenia, to correlate substance use in schizophrenia with various socio-demographic variables and to assess the relationship between the duration of schizophrenia and pattern of substance use. Method: 104 schizophrenia preceded substance use subjects attending both outpatient and inpatient department of Masina Hospital, Mumbai were included in the study. Demographic data was collected in a semi- structured proforma and substance use is assessed using Schedules for Clinical Assessment in Neuropsychiatry (SCAN) version-2.1. Obtained data was subjected to statistical analysis. Results: In our study, mean age of the patients was 35.02±8.84 years, predominantly males (68%), majority of them had not completed their high school (70%) and 57% were unemployed. Two-third of the subjects were from urban area and 49% lived in nuclear family. The most common substance of abuse was found to be tobacco (67%), followed by Alcohol (39%) and 44% of them had harmful use, 38% had occasional use of substances and 18% had dependence syndrome. Belonging to age group of 50–60 years, being unemployed, living in nuclear family and being divorcee were associated with using more than one substance.The most common reason of substance were boredom related (51%), to decrease psychotic symptoms (33.6%) and to decrease medication related side effects (23%). 52% of the subjects had up to 2 hospitalizations, 21.15% had 3-5 hospitalizations, 23.1% had 5-10 hospitalizations and was significantly associated with pattern of substance use. Conclusions: Problem use of drugs and alcohol by people with schizophrenia is greater than in the general population and is known to worsen the prognosis. This warrants proper evaluation, diagnosis and integrated service to tackle dual diagnosis patients holistically to ensure favorable outcome of this dual diagnosis.

Keywords: Schizophrenia; Substance Use Disorders; Tobacco; Dual Diagnosis.