Prevalence and correlates of depression with atypical symptoms in Hong Kong

Previous studies of atypical depression have been conducted in Western communities. There has been no community-based epidemiological study of atypical depression that covers the entire spectrum of bipolar disorders. The aim of the present study was to examine the 12 month prevalence of atypical depression and the differences in demographic and clinical profiles between depressed patients with and without atypical symptoms in the Chinese adult population of Hong Kong.

A random sample of 3016 Chinese adults completed a telephone-based structured interview that examined their 12 month prevalence of major depressive episode. Atypical depression was defined as major depressive episode with hypersomnia and increased weight or appetite. Major depressive episode with and without atypical symptoms were compared on sociodemographic variables, number of depressive and manic/hypomanic symptoms, proportion of having lifetime mania/hypomania, suicidality, family psychiatric history, help-seeking behaviour, level of distress and role impairment.

The 12 month prevalence of atypical depression was 1.3%. Compared to non-atypical depression, atypical depression was associated with female gender, soft (subthreshold) bipolar II disorder, family psychiatric history, higher suicidality, more help-seeking from psychiatrists, and more depressive and manic/hypomanic symptoms. There was no difference in levels of distress or impairment.

Although limited by the lack of detailed information on comorbidity, bipolar family history, and age of onset, the findings support the hypothesis that atypical depression among Chinese people in Hong Kong exhibited prevalence and correlates similar to those found in Western epidemiological and clinical studies. Further research is warranted to examine its association with hypomania and how atypical depression may occupy a nosological position between typical unipolar depression and bipolar spectrum disorders.