This review aimed to summarize longitudinal research about the interplay between sleep, mental health, and positive well-being in adolescents. Multiple search strategies were applied until 28^th January 2023 to identify relevant research published in peer-reviewed journal articles or available grey literature. A final set of 63 studies were included in the systematic review and 42 in the meta-analysis. Results highlighted that long sleep duration, good sleep quality, and low insomnia symptoms were bidirectionally related to lower internalizing (Sleep T1 → Internalizing symptoms T2: r = -.20, p < .001; Internalizing symptoms T1 → Sleep T2: r = -.21, p < .001) and externalizing (Sleep T1 → Externalizing symptoms T2: r = -.15, p < .001; Externalizing symptoms T1→ Sleep T2: r = -.17, p < .001) symptoms, and to higher levels of psychological well-being (Sleep T1 → Psychological well-being T2: r = .15, p < .001; Psychological well-being T1 → Sleep T2: r = .15, p < .05). Moreover, good sleep was positively related to higher subjective well-being at a later time point (r = .18, p < .001). Overall, these findings suggest a bidirectional relation between different aspects of sleep, mental health, and positive well-being.

Insomnia is a prevalent disorder and it leads to relevant impairment in health-related quality of life. Recent clinical guidelines pointed out that Cognitive-Behavior Therapy for Insomnia (CBT-I) should be considered as first-line intervention. Nevertheless, many other interventions are commonly used by patients or have been proposed as effective for insomnia. These include melatonin, light exposure, exercise, and complementary and alternative medicine. Evaluation of comparable effectiveness of these interventions with first-line intervention for insomnia is however still lacking. We conducted a systematic review and network meta-analysis on the effects of these interventions. PubMed, PsycInfo, PsycArticles, MEDLINE, and CINAHL were systematically searched and 40 studies were included in the systematic review, while 36 were entered into the meta-analysis. Eight network meta-analyses were conducted. Findings support effectiveness of melatonin in improving sleep-onset difficulties and of meditative movement therapies for self-report sleep efficiency and severity of the insomnia disorder. Some support was observed for exercise, hypnotherapy, and transcranial magnetic resonance, but the number of studies for these interventions is still too small. None of the considered interventions received superior evidence to CBT-I, which should be more widely disseminated in primary care.

Sleep is fundamental for adolescents’ healthy development but undergoes dramatic changes in quantity and quality due to the conflict between biological and social rhythms. Insufficient sleep has been associated with worse physical health status and irregular eating behaviors in adolescents. This review aims to systematically synthesize the longitudinal associations between adolescents’ sleep dimensions (i.e., duration, timing, quality, and insomnia symptoms) and physical health indicators (i.e., anthropometric indices, fat percentage, and risk of obesity), eating behaviors, and nutritional aspects (i.e., type of diet related to the intake of specific foods and nutrients, amount and timing of food consumption, energy expenditure). A total of 28 longitudinal studies were included. The meta-analytic results showed that longer sleep duration, better sleep quality, and lower insomnia symptoms were associated with lower BMI and fat percentage and that shorter sleep duration (<7 h) and lower sleep quality were associated with a higher risk of obesity. Conversely, anthropometric indices were not related to sleep over time. Limited literature examined the bidirectional association between adolescents’ sleep and their eating behaviors and nutritional aspects. Such knowledge sheds new light on the role of sleep for adolescents’ health, highlighting the need to examine further the interplay between these variables.