Understanding delayed sleep-wake phase disorder (DSWPD): Mechanisms, comorbidities, and evolving approaches to diagnosis and treatment

Background: Delayed Sleep-Wake Phase Disorder (DSWPD) is a circadian rhythm disorder marked by a consistent and distressing delay in sleep timing relative to societal norms. While traditionally viewed as a circadian phase disorder, growing evidence shows psychological, behavioural, and physical health factors interact with circadian biology to influence onset, maintenance, and outcomes. Purpose: of review: This review synthesises recent literature on DSWPD's multifactorial nature, focusing on aetiology, nosology, comorbidities, and treatment. It highlights emerging evidence supporting a multidimensional diagnostic approach and personalised, multimodal management. Recent findings: Some individuals with DSWPD exhibit a significantly delayed circadian phase, while others show normal circadian timing but persistently delayed sleep behaviour. A spectrum approach or subtyping into circadian and behavioural variants has been proposed. Comorbidities with psychiatric conditions including depression, anxiety, ADHD and autism are common and may affect treatment response. Chronobiotic treatments remain core, but cognitive-behavioural and psychotherapeutic interventions are increasingly essential, especially in non-circadian or comorbid cases. Advances in wearable technology and circadian modelling offer promising tools for diagnosis, monitoring, intervention. DSWPD is heterogeneous and requires an integrative, individualised approach considering circadian biology, behaviour and psychiatric comorbidities. A multidimensional diagnostic and treatment model could improve outcomes and functioning.