Depression underdiagnosis: Prevalence and associated factors. A population-based study

Despite its high prevalence and negative consequences, depression is often underdiagnosed. We aimed to estimate the prevalence and sociodemographic and health related factors associated with depression underdiagnosis among a nationally representative population-based sample in Brazil. Method: We used data from 70,806 participants (15-107 years old) of the Brazilian National Survey (PNS 2019). Depression underdiagnosis was considered for participants with a Patient Health Questionnaire-9 (PHQ-9) score >9 and with no diagnosis made by a health provider. Logistic regression models were performed to assess the crude and adjusted association between depression underdiagnosis and sociodemographic and health related factors. Population attributable risk fractions were calculated for significant predictors. Results: The prevalence of depression (according the PHQ-9) was 11.2% (IC95% 10.8:11.7). Depression underdiagnosis prevalence was 63.6% (IC95% 62.0%:65.2%) and was more frequent among male, elderly population, those with lower income, lower schooling, living in the North/Central region of the country, with best health perception, lower number of chronic disease and medical appointments. A significant percentage of depression underdiagnosed cases in Brazil in 2019 would be prevent by improving education (10.18%), income (3.99%), access to health visits (5.59%) and addressing barriers for depression diagnosis among males (5.44%), elderlies (3.32%), and population from the North region (8.29%). Conclusion(s): depression underdiagnosis is common in Brazil. Preventive measures should target the sociodemographic and health related factors associated with depression underdiagnosis.