Rapid onset of comorbidity of common mental disorders: findings from the Netherlands Mental Health Survey and Incidence Study (NEMESIS)

Objective: In a cohort of subjects with no history of psychopathology, we determined a 3-year incidence and the risk factors of comorbid and pure mood, anxiety and substance use disorders. Method: Data were obtained from the Netherlands Mental Health Survey and Incidence Study (NEMESIS), a longitudinal community study in which 4796 adults were interviewed in 1996, 1997 and 1999 with the Composite International Diagnostic Interview. Results: Of 2869 cases at risk, 10.8% developed an incident disorder within 3 years, of which 16.1% was comorbid. Neuroticism, childhood trauma and parental psychiatric history were more strongly associated with comorbid than with pure disorders. No differences emerged in events occurring in the first year after baseline, but events in the period thereafter showed markedly stronger associations with comorbidity and pure mood disorder than with pure anxiety and substance use disorder. Functional disability was also linked more strongly to comorbidity and pure mood disorder. Conclusion: Clear risk factors exist for the rapid onset of comorbidity. Interventions are needed to prevent rapid comorbidity in subjects who recently developed a primary disorder.