Background: Community-based studies of the rates and profile of depression among Africans
are still sparse.
Methods: As part of theWorldMental Health Surveys initiative, a clusteredmulti-stage sampling of
households in 21 of Nigeria's 36 states (representing 57% of the national population) was
implemented to select adults aged 18 years and over (N=6752) for face-to-face interviews using
the Composite International Diagnostic Interview (CIDI 3.0). Diagnosis of major depressive
episode (MDE) was based on the criteria of the Diagnostic and Statistical Manual, 4th edition.
Results: Lifetime and 12-month estimates of MDE were 3.1% (standard error 0.3) and 1.1% (s.e. 0.1),
receptively. Increasing age was associated with higher estimates of positive responses to stem
(screen) questions for depression and of lifetime disorders among stem-positive respondents. The
mean age of onset was about 29.2 years. The median (inter quantile range, IQR) duration of an
episode among lifetime cases was 1.0 (2.0–2.4) year and the median (IQR) number of lifetime
episodes was 1.5 (2.0–2.8). MDE was highly comorbid with anxiety disorders, musculoskeletal
conditions, chronic pain and ulcer. The odds ratio of lifetime suicide attempt among persons with
lifetime MDE was 11.6 (95% confidence interval, 3.9–34.9). Over 25% of 12-month cases were rated
as severely disabled in the performance of usual roles. Only 16.9% (s.e. 5.0) of 12-month cases had
received any treatment.
Limitations: All data were based on self-reports.
Conclusion: MDE, defined according to DSM-IV, is a risk factor for mental and physical comorbidity
as well as disability in Nigerians. Age-related telescoping or denial may partly explain the low rates
in this young population.