The circadian rhythm and technology: melatonin dysfunction as a mechanism of depression

The circadian rhythm regulates fundamental physiological functions such as sleep, hormone secretion, and metabolism, being primarily coordinated by melatonin, whose production is modulated by the presence of light perceived by the suprachiasmatic nucleus of the hypothalamus. In the current context, marked by the increasing use of electronic devices, excessive exposure to blue light - especially at night - has proven to be a critical factor in the dysregulation of this cycle, delaying melatonin release and compromising sleep quality. Scientific evidence indicates that adolescents exposed to more than two hours of screen time daily show a higher prevalence of sleep disorders, depressive and anxious symptoms, as well as shorter sleep duration. The neurophysiological mechanisms of this interference involve the suppression of melatonin via retinohypothalamic pathways, resulting in increased sleep latency and reduced sleep quality. In light of these findings, this integrative review article discusses the effects of blue light on the circadian system and mental health, proposing management strategies such as limiting screen time, using filters, and promoting digital education. The need for multidisciplinary and personalized approaches is highlighted to mitigate the impacts of nighttime screen exposure and to promote chronobiological balance and psychological well-being in adolescents.