Prevalence of Substance Abuse in Schizophrenia: Demographic and Clinical Correlates

TLDR

Methodological shortcomings in prior studies—such as inadequate diagnostic rigor, small samples, and failure to assess multiple substance types—have obscured the true prevalence of substance abuse in schizophrenia, which appears comparable to the general population except for potentially higher stimulant and hallucinogen use. The study examined 149 recently hospitalized DSM‑III‑R patients with schizophrenia spectrum disorders, analyzing how demographics, diagnosis, illness history, and symptom profiles relate to substance abuse. Findings revealed that gender, age, race, and socioeconomic status strongly predict substance abuse, with stimulant users hospitalized earlier and more often diagnosed with schizophrenia but showing similar symptoms, while cannabis users had fewer symptoms and hospitalizations, indicating environmental factors influence abuse patterns.

Abstract

Methodological issues involved in assessing the prevalence of substance abuse in schizophrenia are discussed, and previous research in this area is comprehensively reviewed. Many studies suffer from methodological shortcomings, including the lack of diagnostic rigor, adequate sample sizes, and simultaneous assessment of different types of substance abuse (e.g., stimulants, sedatives). In general, the evidence suggests that the prevalence of substance abuse in schizophrenia is comparable to that in the general population, with the possible exceptions of stimulant and hallucinogen abuse, which may be greater in patients with schizophrenia. Data are presented on the association of substance abuse with demographics, diagnosis, history of illness, and symptoms in 149 recently hospitalized DSM-III-R schizophrenic, schizophreniform, and schizoaffective disorder patients. Demographic characteristics were strong predictors of substance abuse, with gender, age, race, and socioeconomic status being most important. Stimulant abusers tended to have their first hospitalization at an earlier age and were more often diagnosed as having schizophrenia, but did not differ in their symptoms from nonabusers. A history of cannabis abuse was related to fewer symptoms and previous hospitalizations, suggesting that more socially competent patients were prone to cannabis use. The findings show that environmental factors may be important determinants of substance abuse among schizophrenic-spectrum patients and that clinical differences related to abuse vary with different types of drugs.