Sleep and circadian rhythm in psychiatry

Sleep disturbances are both symptoms and causal contributors to nearly every psychiatric disorder, yet the bidirectional mechanisms remain poorly understood. Disrupted circadian rhythms alter neurotransmitter cycling, glymphatic clearance of metabolic waste, and immune function. Interventions like CBT for insomnia (CBT-I), chronotherapy, light therapy, and orexin receptor antagonists show promise, but optimal timing, personalization based on chronotype, and integration with other psychiatric treatments require further investigation.