Background: Cross-national studies have found, unexpectedly, that mental disorder prevalence is higher in high-income relative to low-income countries, but few rigorous studies have been conducted in very low-income countries. This study assessed mental disorders in Nepal, employing unique methodological features designed to maximize disorder detection and reporting.
Methods: In 2016-2018, 10714 respondents aged 15-59 were interviewed as part of an ongoing panel study, with a response rate of 93%. The World Mental Health version of the Composite International Diagnostic Interview (WMH-CIDI 3.0) measured lifetime and 12-month prevalence of selected anxiety, mood, alcohol use, and impulse control disorders. Lifetime recall was enhanced using a life history calendar.
Results: Lifetime prevalence ranged from 0.3% (95% CI 0.2-0.4) for bipolar disorder to 15.1% (95% CI 14.4-15.7) for major depressive disorder. The 12-month prevalences were low, ranging from 0.2% for panic disorder (95% CI 0.1-0.3) and bipolar disorder (95% CI 0.1-0.2) to 2.7% for depression (95% CI 2.4-3.0). Lifetime disorders were higher among those with less education and in the low-caste ethnic group. Gender differences were pronounced.
Conclusions: Although cultural effects on reporting cannot be ruled out, these low 12-month prevalences are consistent with reduced prevalence of mental disorders in other low-income countries. Identification of sociocultural factors that mediate the lower prevalence of mental disorders in low-income, non-Westernized settings may have implications for understanding disorder etiology and for clinical or policy interventions aimed at facilitating resilience.
Keywords: Low-income country; Nepal; mental disorder prevalence.