(1) Background: Ethnic minorities exhibit a higher prevalence of post-traumatic stress disorder (PTSD), while results for problematic substance use among ethnic groups remain mixed. PTSD and problematic substance use often co-occur; however, the impact of ethnicity on this association has not yet been investigated. (2) Methods: Self-report data on problematic alcohol/cannabis use (AUDIT/CUDIT) and presence of severe PTSD symptoms (PSS-SR) of N = 22,841 participants of Dutch (n = 4610), South-Asian Surinamese (n = 3306), African Surinamese (n = 4349), Ghanaian (n = 2389), Turkish (n = 3947), and Moroccan (n = 4240) origin were available from the HELIUS study. (3) Results: We found a positive association between the presence of severe PTSD symptoms and problematic alcohol and cannabis use. Ethnicity did not moderate the association between the presence of severe PTSD symptoms and problematic alcohol/cannabis use. (4) Conclusions: We demonstrated the relationship between the presence of severe PTSD symptoms and problematic alcohol/cannabis use in a multi-ethnic sample. The relationship between the presence of severe PTSD symptoms and problematic alcohol/cannabis use was similar between ethnic groups. We recommend screening for PTSD symptoms in those exhibiting problematic substance use and vice versa, regardless of ethnic background.
Keywords: Healthy Life in an Urban Setting Study; alcohol use; cannabis use; ethnic minority; post-traumatic stress disorder (PTSD).