Impact of sleep and circadian rhythms on addiction vulnerability in adolescents

Abstract

Sleep homeostasis and circadian function are important maintaining factors for optimal health and well-being. Conversely, sleep and circadian disruptions are implicated in a variety of adverse health outcomes including substance use disorders (SUDs). These risks are particularly salient during adolescence. Adolescents require 8–10 hours of sleep per night, although few consistently achieve these durations. A mismatch between developmental changes and social/environmental demands contributes to inadequate sleep. Homeostatic sleep drive takes longer to build, circadian rhythms naturally delay, and sensitivity to the phase-shifting effects of light increases, all of which lead to an evening preference (i.e., chronotype) during adolescence. On the other hand, school start times are often earlier and use of electronic devices at night increases, leading to disrupted sleep and circadian misalignment (i.e., social jet-lag). Social factors (e.g., peer influence) and school demands further impact sleep and circadian rhythms. To cope with sleepiness, many teens regularly consume highly caffeinated energy drinks and other stimulants, creating further disruptions in sleep. Chronic sleep loss and circadian misalignment enhance developmental tendencies towards increase reward sensitivity and impulsivity, increasing the likelihood of engaging in risky behaviors, and exacerbating the vulnerability to substance use and SUDs. We review the neurobiology of brain reward systems and the impact of sleep and circadian rhythms changes on addiction vulnerability in adolescence, and suggest areas that warrant further research.