Background: In the context of the current debate on the clinical relevance of atypical depression, the present study investigated the prevalence and specific characteristics of the disorder in depressed primary care outpatients and compared patients with atypical and with the prototypical form of depression ("non-atypical" depression).
Methods: 403 patients were examined using the Composite International Diagnostic Interview, Inventory of Depressive Symptomatology, Hamilton Depression Scale and DSM-IV criteria. Configurational frequency analyses (CFA) were conducted to identify non-random configurations of symptoms. Moreover, tests for independent sample comparisons were applied.
Results: The prevalence of atypical depression in our sample of depressed patients was 26.3%. CFA revealed one significant symptom pattern: mood reactivity without additional atypical features (p<0.000001). A significant difference emerged between patients suffering from atypical versus non-atypical depression in terms of severity (p< or =0.001).
Limitations: The sample size was modest.
Conclusions: A considerable proportion of depressed primary care outpatients may suffer from atypical depression which may contribute to under-recognition of depression in primary care. Results of CFA indicated the significance of mood reactivity which may also occur in depressed patients without additional atypical symptoms. Patients with atypical depression may suffer from less severe depression as compared to patients with non-atypical depression.