Delayed sleep–wake phase disorder in adolescents: diagnosis, psychiatric comorbidity, and management

Delayed sleep–wake phase disorder (DSWPD) is the most common circadian rhythm sleep wake disorder encountered in clinical settings. It is especially relevant during adolescence, when developmental shifts toward later sleep timing are more frequent. Adolescents with DSWPD typically have persistent difficulty falling asleep and waking at socially conventional times, despite being able to obtain adequate sleep with their preferred schedule. This mismatch between endogenous circadian timing and external demands can lead to school absenteeism, daytime sleepiness, academic decline, and mood disturbance. DSWPD also frequently co-occurs with psychiatric conditions, particularly depression, anxiety, and neurodevelopmental disorders. DSWPD has an identifiable neurobiological basis, characterized by a lengthened endogenous period, heightened circadian system sensitivity to evening light, and clock gene variants in a minority of individuals. These mechanisms provide the rationale for pharmacological and photic phase-advancing treatment. Diagnosis is made primarily on clinical history supported by sleep diaries and actigraphy. Polysomnography is not routinely required unless another sleep disorder is suspected. Dim-light melatonin onset may be useful in selected cases, but this is not necessary for routine diagnosis. Treatment currently focuses on circadian phase advancement through timed melatonin, morning light exposure, and behavioral stabilization of sleep–wake schedules. Although the evidence base in adolescents remains limited in some areas, early recognition and practical circadian interventions may substantially improve functioning. This narrative mini-review summarizes the clinical presentation, circadian neurobiology, psychiatric relevance, diagnostic assessment, and management of adolescent DSWPD, with emphasis on practical issues encountered in mental health and pediatric sleep settings.