Global inequalities in mental health problems: understanding the predictors of lifetime prevalence, treatment utilisation and perceived helpfulness across 111 countries

Socio-economic inequalities in mental health problems are found in measures covering prevalence, treatment utilisation, and treatment helpfulness. However, whether these inequalities exist globally and what factors explain between-country variation is unclear. We use a nationally representative individual-level survey dataset (Wellcome Global Monitor, 2020) in 111 countries (N = 117,088) to test if socio-economic factors (household income, education), psycho-social factors (stigma perception, trust in health professionals) and country-level factors (GDP, Gini, health expenditure) predict (1) self-reported lifetime prevalence of anxiety and depression symptomology, (2) treatment utilisation and (3) perceived treatment helpfulness talking to a mental health professional and taking prescribed medication. Multi-level logistic regression models were used. Across both HICs and LMICs, being in the richest income quintile within each country is associated with a lower probability of experiencing symptoms of anxiety and depression compared to the poorest quintile (OR = 0.67 CI [0.64-0.70]), as well as a higher probability of talking to a mental health professional (OR = 1.25[1.14-1.36]), and of perceiving this treatment as very helpful (OR = 1.23[1.07-1.40]). However, being among the richest income quintile is not associated with taking prescribed medication (OR = 0.97[0.89-1.06]) and its perceived helpfulness (OR = 1.06[0.94-1.21]) across all countries. Trust in health practitioners is associated with higher mental health professional utilisation (OR = 1.10[1.06-1.14]) and helpfulness (OR = 1.32[1.25-1.40]). This analysis reveals a global 'triple inequality in mental health', whereby disadvantages of lower SES individuals persist in three outcomes (lifetime prevalence, treatment utilisation and helpfulness). Treatment utilisation and helpfulness also vary by trust in healthcare professionals and treatment type. Policymakers must address all three inequalities and their fundamental causes.