Figure 1.

Neurobiological modifications in adolescents, circadian rhythm changes and mechanisms of development of psychiatric disorders. Legend. The adolescent brain faces many changes during a short period related to neurobiological modifications combined with psychosocial and environmental factors. Deep brain areas such as the limbic and reward system areas (ventral striatum and amygdala) increase their neural activity (top on the left). This temporary hyperfunction of dopaminergic circuits can lead to emotional dysregulation (center on the left), augmenting the risk of developing psychological malaise and psychiatric disorders (bottom on the right) [12]. Moreover, circadian rhythm modifications with delayed melatonin secretion (top center) occur during adolescence. These changes, together with environmental and psychosocial factors (increased social interaction and use of technology at nighttime) (top on the right), may result in sleep disturbances (sleep deprivation, circadian rhythm disorders, insomnia) (middle on the right) [13,14]. Of note, sleep loss may decrease functional connectivity between the top-down control regions of the prefrontal cortex and the amygdala [1]. Sleep disorders can drive/worsen emotional dysregulation, which in turn may contribute to the onset and/or maintenance of sleep disturbances. Moreover, sleep disorders may increase the risk of psychological problems and psychiatric disorders, which in turn may induce and/or maintain sleep disturbances [15,16,17].