Loneliness is associated with poor mental health, social-environmental factors, and health risk behaviours among national samples of in-school adolescents in four Caribbean countries.

The goal of the study was to estimate associations of loneliness with poor mental health, social-environmental and health risk behaviour indicators among adolescents in the Caribbean. Cross-sectional national 'Global School-Based Student Health Survey (GSHS)' data of four Caribbean countries ( = 9,143 adolescents) in 2016-2017 were analysed. In adjusted logistic regression analysis, loneliness was significantly positively associated with all five poor mental health outcomes (having no close friends, anxiety-induced sleep disturbance, suicidal ideation, suicide plan and suicide attempt). Regarding social-environmental outcomes, loneliness was significantly positively associated with bullying victimization, having been physically attacked, involvement in fighting, frequent experiences of hunger and passive smoking (in particular among boys). In terms of health risk behaviour outcomes, loneliness significantly increased the odds for current tobacco use, ever drunk, trouble from alcohol use, ever amphetamine use, multiple sexual partners, leisure-time sedentary behaviour, injury and frequent soft drink consumption. In addition, among boys, loneliness increased the likelihood for current cannabis use. Loneliness is associated with poorer mental health, social-environmental risk factors and health risk behaviours. Results show the importance of taking loneliness into account in a number of mental, social, and physical health factors.