OBJECTIVE: The primary objective of this study was to assess and describe perceived cognitive dysfunction amongst Asian patients diagnosed with MDD. The secondary objective was to explore the associations between depression severity, perceived cognitive dysfunction and functional disability.

METHODS: This was a multi-country, multi-centre, cross-sectional study. Adults with a current episode of MDD were recruited from 9 university/general hospital clinics in Asia. During a single study visit, psychiatrists assessed depression severity (Clinical Global Impression-Severity, CGI-S); patients completed questionnaires assessing depression severity (Patient Health Questionnaire-9 items, PHQ-9), perceived cognitive dysfunction (Perceived Deficit Questionnaire-Depression, PDQ-D) and functional disability (Sheehan Disability Scale, SDS).

RESULTS: Patients (n=664), predominantly women (66.3%), were aged 46.5±12.5 years, lived in urban areas (81.3%) and were employed (84.6%). 51.5% of patients were having their first depressive episode; 86.7% were receiving treatment; 82.2% had a current episode duration >8 weeks. Patients had mild-to-moderate depression (CGI-S=3.3±1.0; PHQ-9=11.3±6.9). Patients reported perceived cognitive dysfunction (PDQ-D=22.6±16.2) and functional disability (SDS=11.3±7.9). PHQ-9, PDQ-D and SDS were moderately-to-highly correlated (PHQ-9 and SDS: r=0.72; PHQ-9 and PDQ-D: r=0.69; PDQ-D and SDS, r=0.63). ANCOVA showed that after controlling for patient-reported depression severity (PHQ-9), perceived cognitive dysfunction (PDQ-D) was significantly associated with functional disability (SDS) (p<0.001).

METHOD: Data were collected from 5536 patients at 50 sites in 32 countries on six continents. Onset occurred at 456 locations in 57 countries. Variables included solar insolation, birth-cohort, family history, polarity of first episode and country physician density.

RESULTS: There was a significant, inverse association between the maximum monthly increase in solar insolation at the onset location, and the age of onset. This effect was reduced in those without a family history of mood disorders and with a first episode of mania rather than depression. The maximum monthly increase occurred in springtime. The youngest birth-cohort had the youngest age of onset. All prior relationships were confirmed using both the entire sample, and only the youngest birth-cohort (all estimated coefficients P < 0.001).