Purpose: To determine the prevalence of substance use disorders (SUDs) in patients with schizophrenia in a sample from South Africa and compare the clinical and demographic correlates in those with and without co-occurring SUDs.
Methods: Patients with schizophrenia were interviewed using the Xhosa version SCID-I for DSM-IV. We used logistic regression to determine the predictors of SUDs.
Results: In the total sample of 1420 participants, SUDs occurred in 47.8%, with the most prevalent SUD being cannabis use disorders (39.6%), followed by alcohol (20.5%), methaqualone (6.2%), methamphetamine (4.8%) and other SUDs (cocaine, ecstasy, opioids, 0.6%). Polydrug use occurred in 40%, abuse occurred in 13.5%, and 39.6% had at least one substance dependence diagnosis. Significant predictors of any SUD were younger age (41-55 vs. 21-30: OR = 0.7, 95% CI = 0.5-0.9), male sex (OR = 8.6, 95% CI = 5.1-14.6), inpatient status (OR = 1.7, 95% CI = 1.3-2.1), post-traumatic stress symptoms (OR = 4.6, 95% CI = 1.6-13.3), legal (OR = 3.4, 95% CI = 2.0-5.5) and economic problems (OR = 1.4, 95% CI = 1.0-2.0). Methamphetamine use disorders occurred significantly less often in the Eastern compared to the Western Cape provinces. Inpatient status and higher levels of prior admissions were significantly associated with cannabis and methamphetamine use disorders. Post-traumatic stress symptoms were significantly associated with alcohol use disorders. Anxiety disorders were associated with other SUDs.
Conclusion: SUDs occurred in almost half of the sample. It is important for clinicians to identify the presence of SUDs as their presence is associated with characteristics, such as male sex, younger age, inpatient status, more prior hospitalisations, legal and economic problems, PTSD symptoms and anxiety.
Keywords: Correlates; Prevalence; Schizophrenia; South Africa; Substance use.