Low comorbid obsessive-compulsive disorder in patients with major depressive disorder – Findings from a European multicenter study

Background This cross-sectional European multicenter study examined the association between major depressive disorder (MDD) and comorbid obsessive-compulsive disorder (OCD). Methods Socio-demographic, clinical, and treatment features of 1346 adult MDD patients were compared between MDD subjects with and without concurrent OCD using descriptive statistics, analyses of covariance (ANCOVA), and binary logistic regression analyses. Results We determined a point prevalence of comorbid OCD in MDD of 1.65%. In comparison to the MDD control group without concurrent OCD, a higher proportion of patients in the MDD + comorbid OCD group displayed concurrent panic disorder (31.81% vs 7.77%, p<.001), suicide risk (52.80% vs 44.81%, p=.04), polypsychopharmacy (95.45% vs 60.21%, p=.001), and augmentation treatment with antipsychotics (50.00% vs 25.46%, p=.01) and benzodiazepines (68.18% vs 33.31%, p=.001). Moreover, they were treated with higher mean doses of their antidepressant drugs (in fluoxetine equivalents: 48.99 mg/day ± 18.81 vs 39.68 mg/day ± 20.75, p=.04). In the logistic regression analyses, comorbid panic disorder (odds ratio (OR)=4.17, p=.01), suicide risk (OR=2.56, p=.04), simultaneous treatment with more psychiatric drugs (OR=1.51, p=<.05), polypsychopharmacy (OR=14.29, p=.01), higher antidepressant dosing (OR=1.01, p=<.05), and augmentation with antipsychotics (OR=2.94, p=.01) and benzodiazepines (OR=4.35, p=.002) were significantly associated with comorbid OCD. Conclusion In summary, our findings suggest that concurrent OCD in MDD (1) has a low prevalence rate compared to the reverse prevalence rates of comorbid MDD in OCD, (2) provokes higher suicide risk, and (3) is associated with a characteristic prescription pattern reflected by a high amount of polypsychopharmaceutical treatment strategies comprising particularly augmentation with antipsychotics and benzodiazepines.