Psychiatric Comorbidities Modify the Association Between Childhood ADHD and Risk for Suicidality: A Population-Based Longitudinal Study.

OBJECTIVE

The objective of this study was to evaluate the effect of psychiatric comorbidities on the association between childhood ADHD and suicidality among adults.

METHOD: Subjects were recruited from a population-based birth cohort. Participating adult subjects with childhood ADHD and non-ADHD controls were administered a structured psychiatric interview to assess suicidality and psychiatric comorbidities. Associations were assessed using logistic regression.

RESULTS

Compared with controls, ADHD cases were significantly more likely to meet criteria for suicidality. Subjects with childhood ADHD who met criteria for generalized anxiety disorder had a higher than expected risk of suicidality with an observed odds ratio of 10.94 (95% confidence interval [4.97, 24.08]) compared with an expected odds ratio of 4.86, consistent with a synergistic interaction effect. Significant synergistic interactions were also observed for hypomanic episode and substance-related disorders.

CONCLUSION

Childhood ADHD is significantly associated with adult suicidal risk. Comorbidity between ADHD and some psychiatric disorders is associated with a higher suicidal risk than expected.