A Systematic Review on Insomnia and Circadian Rhythms Desynchronization in Obsessive-Compulsive Disorder: From Childhood to Adulthood.

Obsessive-compulsive disorder is frequently accompanied by sleep disturbances, particularly insomnia and circadian dysregulation. These conditions are increasingly recognised not only as comorbidities but also as factors potentially influencing the severity and course of obsessive-compulsive symptoms. This systematic review synthesises findings from 28 studies investigating the association between obsessive-compulsive disorder, insomnia and circadian alterations across different age groups. Insomnia was found to be highly prevalent among individuals with obsessive-compulsive disorder and associated with greater symptom severity, especially regarding intrusive thoughts and cognitive-affective dysregulation. Circadian disruptions, such as delayed sleep phase, evening chronotype, and atypical hormonal rhythms, were frequently observed and related to emotional instability and clinical variability. These results underscore the importance of systematically assessing and addressing sleep-related disturbances in patients with obsessive-compulsive disorder. Integrating sleep and circadian-focused strategies into clinical care may improve treatment outcomes and provide insight into underlying neurobiological mechanisms.