Comorbid generalized anxiety disorder and its association with quality of life in patients with major depressive disorder

The comorbidity of major depressive disorder (MDD) and generalized anxiety disorder (GAD) is common and often predicts poorer outcomes than either disorder alone. This study aimed to examine the prevalence of comorbid GAD and its association with quality of life (QOL) among MDD patients. A total of 1225 psychiatric outpatients were screened using the Hospital Anxiety and Depression Scale (HADS). Those who scored >= 8 on the HADS were interviewed using DSM-IV criteria by two senior psychiatrists. Patients diagnosed with MDD were further assessed using the 9-item Patient Health Questionnaire, Social Support Rating Scale, Pittsburgh Sleep Quality Index, and World Health Organization QOL Scale, brief version (WHOQOL-BREF). Ultimately, 667 patients were diagnosed with MDD, of 71.7% of whom had GAD. Compared to those with MDD alone, comorbid patients had lower scores on the physical (38.64 +/- 10.35 vs. 36.54 +/- 12.32, P = 0.026) and psychological (35.54 +/- 12.98 vs. 30.61 +/- 14.66, P < 0.001) domains of the WHOQOL-BREF. The association between comorbid GAD and poor QOL on the two domains remained statistically significant in the multiple linear regression (unstandardized coefficients: -1.97 and -4.65, P < 0.001). In conclusion, the prevalence of comorbid GAD in MDD patients is high, and co-occurring GAD may exacerbate impaired physical and psychological QOL in Chinese MDD patients.