Background: The associations between mental disorders and cancer is unclear. It is also unknown whether associations vary according to life course stage or gender. Methods: The World Health Organization Composite International Diagnostic Interview retrospectively assessed lifetime prevalence of 16 DSM-IV mental disorders in face-to-face household population surveys in 19 countries (n=52,095). Cancer was indicated by self-report of diagnosis. Survival analyses estimated associations between first onset of mental disorders and subsequent cancer. Results: Following adjustment for mental disorder comorbidity, panic disorder, specific phobia and alcohol abuse were associated with cancer (OR 1.3-1.5). The risk of cancer rose with the number of disorders. Depression was more strongly associated with cancers diagnosed early in life (OR 1.7) and not late onset (OR 1.2) and cancer among women (OR 1.5). PTSD also has an association with early cancers. Discussion: This study reveals the magnitude and patterns of the associations between mental disorders and cancer. The findings suggest a link between the two types of conditions and support arguments for early identification and treatment of mental disorders.
