Purpose: This study aimed at evaluating the comorbidity between DSM-IV obsessive compulsive disorder (OCD) and subthreshold forms and physical diseases in the general population as well as disability associated with comorbidity.
Methods: We used data from the 1998 German Mental Health Survey, a representative survey of the German population. Mental disorders and physical diseases of 4181 subjects (aged 18-65) were cross-sectionally assessed. Mental disorders were diagnosed using the M-CIDI/DIA-X interview. Physical diseases were assessed through a self-report questionnaire and a standardized medical interview. We created three groups of obsessive-compulsive symptoms: (1) no obsessive compulsive symptoms (n = 3,571); (2) obsessive compulsive symptoms (OCS, n = 371; endorsement of OCS (either obsession or compulsion) without fulfilling any core DSM-IV criteria); (3) subthreshold OCD/OCD (n = 239; fulfilling either some or all of the core DSM-IV criteria).
Results: In comparison to subjects without OCS, subjects with subthreshold OCD/OCD showed higher prevalence rates of migraine headaches (OR 1.7; 95% CI 1.1-2.5) and respiratory diseases (OR 1.7; 95% CI 1.03-2.7); subjects with OCS showed higher prevalence rates of allergies (OR 1.6; 95% CI 1.1-2.8), migraine headaches (OR 1.9; 95% CI 1.4-2.7) and thyroid disorders (OR 1.4; 95% CI 1.01-2.0). Subjects with both OCS and physical disease reported the highest number of days of disability due to physical or psychological problems during the past 30 days compared to subjects with only OCS, only physical disease or neither of them.
Conclusions: OCD and subthreshold forms are associated with higher comorbidity rates with specific physical diseases and higher disability than subjects without OCS. Possible etiological pathways should be evaluated in future studies and clinicians in primary care should be aware of these associations.