Sleep quality paramount in teens’ mental health

Sleep quality is a central determinant of adolescent mental health and well-being, while diet and physical activity play a secondary, but nevertheless important, role, according to a recent cross-sectional study.

“The findings from our study add to this literature by showing that when tested side-by-side, sleep quality significantly outranked other health behaviours in the prediction of mental health and well-being,” the researchers said.

A total of 1,111 young adults (aged 18–25 years; 28.4 percent male) participated and accomplished an online survey on baseline demography, key predictors of mental health, and mental health outcomes such as depressive symptoms and well-being. On average, participants slept for around 7 hours per night, and mean quality score, as measured by a non-validated, four-point scale, was 1.63, indicating that most were “a little or somewhat refreshed” in the morning. [Front Psychol 2020;doi:10.3389/fpsyg.2020.579205]

Participants exercised approximately thrice per week, and they ate around three servings of fruit and vegetables per day.

In terms of mental health outcomes, the study population displayed heightened levels of depressive symptoms, earning a mean score of 19 on the Centre for Epidemiological Studies Depression Scale (CES-D); a score above 16 indicated risk of clinical depression. The overall well-being, however, was slightly better, with a mean score of 5 on the Flourishing Scale.

Hierarchical regression analysis found sleep to be the strongest protective factor against depressive symptoms, both in terms of quantity (b, –3.630±0.970) and quality (b, –3.788±0.357; p<0.001 for both). Sleep quality was also the strongest predictor for flourishing (b, 0.344±0.034; p<0.001), whereas sleep quantity was not significantly related.

Looking at the visualizations, however, sleep quantity had a U-shaped interaction with depressive symptoms, such that only those who slept between 8–12 hours per night, and not more or less, had the best mental health. Sleep quality, on the other hand, was linearly associated: higher sleep quality was linked to lower depressive levels.

Physical activity was the second most important factor for depressive symptoms (b, –0.526±0.180; p<0.01) and flourishing (b, 0.091±0.017; p<0.001) and showed a similarly linear, but more attenuated, effect as sleep quality. Intake of raw fruits and vegetables was linked only with flourishing, and not with depressive symptoms; consumption of processed fruits and vegetables was not correlated with any of the outcomes.

“Our findings suggest that future lifestyle interventions targeting sleep quality may be most beneficial at improving mental health and well-being. However, physical activity and diet should not be disregarded,” the researchers said.

“Sleep, physical activity, and a healthy diet should be thought of as multiple tools for promoting optimal mental health and well-being, particularly among young adult populations where the prevalence of mental disorders is high and well-being is suboptimal,” they added.