Trends and factors associated with illicit drug use in South Africa: Findings from multiple national population-based household surveys, 2002-2017

Background: Illicit drug use results in considerable global morbidity, but there is little data on its trends and factors associated with it in sub-Saharan Africa. We consider these questions using national data from South Africa for 2002-2017. Methods: We analysed data among individuals aged 15 years or older from five national population-based household surveys in South Africa (2002-2017; n = 89,113). Recent drug use was defined as the last threemonths use of illicit drugs, i.e., any use of cannabis, cocaine, amphetamine, inhalants, sedatives, hallucinogens, opioids, and/or other illicit drugs. Time trends in recent drug use were assessed using logistic regression. Multivariable logistic regression assessed the association between recent drug use and socio-demographic factors and between drug use and sexual risk behaviours, HIV-related and other well-being variables. Results: The prevalence of recent drug use increased from 1.5% to 10.0% from 2002 to 2017, driven by increases in cannabis use (1.5% to 7.8%) and use of opioids (0.01% to 1.6%), cocaine (0.02% to 1.8%), or amphetamines (0.1% to 1.5%). In adjusted analyses, male gender, younger age, living in urban areas, mixed-ancestry or white ethnicity (compared to black-African), and unemployment were positively associated with recent drug use. Recent drug use was associated with: multiple sexual partners (adjusted odds ratio [aOR] 2.13, 95% confidence interval [CI]: 1.80-2.51); sexual debut before 15 years old (aOR 1.70, 95%CI: 1.29-2.23); hazardous/harmful alcohol use (aOR 2.50, 95%CI: 2.14-2.93) or alcohol dependence (aOR 3.33, 95%CI 2.92-3.80); ever experiencing intimate partner violence (aOR 1.56, 95%CI 1.12-2.17); psychological distress (aOR 1.53, 95%CI: 1.28-1.82); and lower chance of ever testing for HIV (aOR 0.89, 95%CI 0.80-1.00). Recent drug use was not associated with HIV positivity, condom use or being on antiretroviral therapy. Conclusion: Illicit drug use has increased substantially in South Africa and is associated with numerous sociodemographic characteristics, higher sexual risk behaviours and other well-being variables.