Prevalence of moderate and high risk substance use and service needs among psychiatric inpatients at Zomba Mental Hospital in Malawi

Includes bibliographical referencesBackground: Mental illness increases risk for substance use and the presence of substance use in people living with mental illness makes diagnosis and treatment of both disorders more complicated. For treatment of either disorder to be successful, both must be identified and treated individually. The substance use burden and service needs of psychiatric inpatients in Malawi are unknown. Objectives: The study aimed to determine prevalence of risky substance use and service needs among psychiatric inpatients. Methods: A cross-sectional study was conducted examining subjective substance use using the World Health Organization Alcohol, Smoking and Substance Involvement Screening Test (ASSIST) version 3.1 in 323 new inpatients aged ≥18 years. The prevalence of risky and lifetime substance use was calculated in addition to bivariate analysis and linear regression. The kappa statistic was calculated to compare diagnosis of substance use during routine clinical assessment on admission with screening using the ASSIST. Results: ASSIST-linked lifetime prevalence for each substance were alcohol 54.8 %, (95 % CI: 49.3-60.1 %), followed by tobacco 43.7 %, (95 % CI: 38.4-49.1 %), and cannabis 39.0 %, (95 % CI: 33.9-44.4 %). No-one reported any use of amphetamine-type stimulants, hallucinogens, or opioids. The prevalence of moderate risk use, requiring brief intervention were tobacco 19.2 %, (95 % CI: 15.3-23.9 %), cannabis 9.9 %, (95 % CI: 7.1-13.7 %), alcohol 7.1 %, (95 % CI: 4.8-10.5 %), sedatives 1.2 %, (95 % CI: 0.4-3.3 %) and cocaine 0.6 %, (95 % CI: 0-2.4 %). High risk use requiring specialist care was identified for alcohol 18.6 %, (95 % CI: 14.7-23.2 %), cannabis 16.7 %, (95 % CI: 13.0-21.2 %), tobacco 10.8 %, (95 % CI: 7.9 -14.7 %) and inhalants 0.3 %, (95 % CI: -0.1-2.0 %). Interrater agreement for diagnosis of substance use disorder between routine clinical assessment compared to ASSIST questionnaire was Kappa = 0.530 (p < 0.001) which is moderate but statistically significant. The multivariate linear regression to determine the risk factors associated with tobacco, alcohol and cannabis. Males are more likely to use all these substances and have a higher ASSIST score than female patients (p < 0.001). The model indicated that risky alcohol use is significantly higher in Christians than other religions or no religious affiliation (p =.044) while risky cannabis use is significantly higher in rural residents compared to urban residents (p =.042). Conclusions: Results suggest that tobacco, alcohol and cannabis are commonly used among psychiatric inpatients in this population. Most patients use substances at risky levels requiring both brief intervention and specialist care. Although substance use is common, the detection of substance use disorders in admission assessments is moderate and could be improved. The ASSIST questionnaire is useful in screening for substance use in psychiatric inpatient populations and is likely to improve detection and management