Introduction: Substance Use Disorders (SUD) and Major Depression Disorders (MDD) are both causes of disability around the world, and the prevalence of their comorbidity is very high and complicates the clinical management of patients. The alteration of the circadian rhythmic system has been proposed as a factor related to the onset, severity, and course of both disorders, although the exact influence is not yet well defined and less in dual condition.

Methods: Three major databases (Web of Science, Scopus, and PubMed) were selected to search for articles that comprise information about SUD, MDD, and circadian rhythmicity in the last 10 years (2013-2024). Parameters were identical in all databases [("addiction" OR "substance use" OR "dual disorder") AND depression AND ("circadian" OR "sleep-wake")]. Results without one of these parameters; with animal models; or in languages other than English, Spanish, Portuguese or French were excluded.

Results: A total of 613 articles were found. After exclusion of the duplicates, a total of 436 articles were left. From those, more than 20% of those did not have an SUD condition and about a third of the MDD results were mixed with bipolar disorders (BDs). With the application of the inclusion and exclusion criteria, a total of 245 articles were selected.

Conclusion: This work will present the main findings of circadian rhythmicity, including data of the sleep--wake rhythm, with an emphasis on improving our understanding of the multifactorial explanatory model of SUD, MDD, and their comorbidities. It is important to steer future studies aiming at the clarification of the onset and possible treatment outcomes of these disorders. This could lead to more assertive and efficient prevention and treatment programs for both disorders from a more individualized approach.