Predicting the Contribution of Age at First Substance Use and Post-Traumatic Stress Disorder to Later Addiction Severity in a Clinical Sample from Sub-Saharan Africa: Implications for Prevention and Treatment

This study sought to examine the extent to which age at first substance use contributes to later addiction severity and how PTSD affects their relationships. The study enrolled 315 patients from tertiary addiction services in Rwanda. The participants’ mean age at first substance use was 18.64 years (SD = 6.1) old. Age at first substance use had a significant effect ( β = − 0.130, p = .013) on later addiction severity. PTSD showed significant association with later addiction severity ( β = 0.363; p = < .001). The variance explained by age at first substance use and PTSD increased from R 2 adjusted = .013 to 14.7; 14.7, and this was statistically significant with F(8637) = 28.054, p < .001. The study demonstrates that early age at first substance use coupled to PTSD significantly predict more later addiction severity. This suggests prevention and clinical practice that aimed at improving addiction care outcomes should consider addessing potential consequences of associations between PTSD and addiction issues among persons seeking addiction treatment services.