Abstract

Sexual and gender minority youth (SGMY) face unique psychosocial stressors that increase vulnerability to substance use. However, evidence from low- and middle-income countries (LMICs) remains limited. Objective: To compare the lifetime prevalence and age of onset of substance use between LGBTQIAPN+ and cisgender heterosexual adolescents in Brazil. Data were drawn from the Brazilian High-Risk Cohort Study for Mental Health Conditions (BHRC), a longitudinal, community-based study. A total of 1,492 participants aged 9–18 at wave 1 and 12–21 at wave 2 provided complete data on sexual orientation, gender identity, and lifetime use of alcohol, tobacco, cannabis, and cocaine. LGBTQIAPN+ adolescents had higher lifetime prevalence of tobacco (OR = 1.66; 95% CI: 1.22–2.26; p?=?0.001), cannabis (OR = 1.94; 95% CI: 1.42–2.64; p?<?0.001), and cocaine use (OR = 2.28; 95% CI: 1.21–4.13; p?=?0.008) than cisgender heterosexual peers. These differences were driven by participants assigned female at birth, with no significant differences among males. LGBTQIAPN+ females also reported earlier initiation of alcohol (p?=?0.001), tobacco (p?<?0.001), and cannabis (p?<?0.001). Conclusions: Brazilian LGBTQIAPN+ youth, especially females, show elevated substance use and earlier initiation, underscoring the need for targeted, gender-sensitive prevention strategies.