Remarkably, whether individuals with OCD have higher prevalence of SUDs compared with the general population remains unclear. Studies with clinical samples10,11,12,13,14 have reported SUD prevalence similar to that of the general population. Other studies15,16,17 have even suggested that people with OCD might be less likely to use substances owing to risk aversion. In contrast, epidemiological surveys18,19,20,21,22 have found an elevated risk of SUDs in individuals with OCD. However, many clinical studies did not include a control group, and epidemiological surveys often had few cases with OCD, resulting in imprecise estimates. Moreover, the lack of longitudinal and genetically informative data has hindered progress in this field.
