Previous research has unveiled an intriguing positive association between the AB blood group and mental disorders in general. In this study, we compared ABO blood groups with five major groups of mental disorders to attain a higher level of specificity. The analyses were conducted using data from the CoLaus|PsyCoLaus study (N=5111). They revealed that the AB blood group exhibited a positive association with both neurodevelopmental disorders (RR 2.29, CI 1.38-3.82) and substance use disorders (RR 2.25, CI 1.38-3.65) after adjusting for sex and childhood adversities. These associations could be replicated with respect to the familial aggregation of neurodevelopmental and substance use disorders. Large databases are needed to achieve more detailed results related to specific disorders.