BACKGROUND: People with mental disorders are more vulnerable to human immunodeficiency virus (HIV) infection. A part of first-line treatment for HIV, efavirenz, is routinely avoided in patients with mental illness due to the risk of potential aggravation of the mental illness. This study aimed to determine the outcomes of people living with HIV/AIDS who were mental healthcare users admitted to two public-sector psychiatric facilities and who were prescribed an efavirenz-containing regimen. MATERIALS AND METHODS: A retrospective drug utilization study was conducted at two public-sector psychiatric hospitals in the Eastern Cape of South Africa. Patients aged 18 years or older living with HIV were included in the study. Follow-up reviews were conducted at four, 12 and 24 weeks. The patients were seen by doctors at the hospital and notes on progress and medication were recorded in medical records. The files were then reviewed. RESULTS: A total of 37 patients were enrolled. However, just 26 were reviewed at 24 weeks. A total of 43.2% (n=16) were female patients and the average age of the patients was 39.38±8.76 years. At the baseline, 32.4% (n=12) patients were diagnosed with schizophrenia. A total of 81.08% (n=30) of patients experienced an improvement in psychiatric symptoms after 24 weeks. Of these, 43.3% (n=13) were on an efavirenz-containing regimen. CONCLUSION: Majority of the patients demonstrated an improvement in their psychiatric conditions to the extent that they were discharged into the community. This finding suggests that patients with psychiatric disorders on efavirenz can experience stabilisation of their psychiatric symptoms.