Chronotype and substance use disorder: A systematic review with meta-analysis on the impact of circadian misalignment on psychopathology and clinical course.

Circadian rhythms regulate essential biological functions such as sleep, hormonal secretion, mood regulation, and reward processing. Individual differences in circadian preference, known as chronotype, may influence the risk of developing psychiatric disorders. Specifically, evening preference has been associated with emotional dysregulation, impulsive behavior, and increased reward sensitivity, which are key factors in the development and maintenance of substance-related disorders. Despite growing evidence, the relationship between chronotype and substance use disorders has not yet been systematically evaluated. This review aimed to synthesize the available clinical literature and quantitatively assess the association between chronotype and substance use disorders. A systematic search identified studies examining the link between chronotype and diagnostic, symptomatic, or prognostic features of substance use disorders in clinical populations. The review found consistent evidence that evening preference is associated with earlier onset, higher symptom severity, and poorer treatment outcomes. Five studies were included in the meta-analysis. The pooled odds ratio showed that individuals with evening preference had a significantly higher likelihood of being diagnosed with a substance use disorder compared to those with morning preference (pooled odds ratio = 1.55, 95 percent confidence interval: 1.20 to 1.95). These findings suggest that circadian preference is a clinically relevant factor in the assessment and treatment of substance use disorders.