Trends in the perceived body size of adolescent males and females in Scotland, 1990–2014: changing associations with mental well-being

Objectives: This paper explores trends in Scottish adolescents’ body size perceptions and associated mental well-being outcomes. Methods: Data were collected on Scottish 11-, 13-, and 15-year-olds by the Health Behaviour in School-aged Children study between 1990 and 2014 (n = 42,312). Logistic regression was used to examine changes in the prevalence of over- and underweight perceptions. Ordinal and linear regressions were used to examine changes in the association between body perception and mental well-being. Results: Little change was observed in over- or underweight perceptions. However, relative to those perceiving their body as ‘about right’, those perceiving themselves as overweight reported decreasing confidence (all groups), decreasing happiness (11- and 13-year-old girls), and increasing psychological health symptoms (all girls and 15-year-old boys). Perceived underweight is associated with poor well-being, especially in males, but we present little evidence that this is a recent phenomenon. Conclusions: We present evidence suggesting that the association between body size perception and poor mental health in adolescence is changing over time. This may play a role in the recently observed worsening of mental well-being in Scottish adolescents