Melatonin, adolescence, and the brain: An insight into the period-specific influences of a multifunctional signaling molecule.

Melatonin is a neurohormone that is involved in the modulation of a wide range of physiological processes, including maintenance of the circadian rhythm, mediation of photoperiodic information, regulation of the sleep-wake cycle, synchronization of cell physiology, antioxidant defense, and immune-modulation. Although there are reports of increasing use of melatonin in the management of a number of health conditions, evidence exists that is suggestive of deleterious effects of melatonin administration on brain and reproductive development in the prepubertal and pubertal periods that are within the teenage years. In this review, we examine the influences of endogenous and exogenous melatonin on the adolescent brain, with specific reference to its involvement in the evolution of brain functions, brain structure, sleep regulation, and modulation of behaviors in health or disease.