Chronotype, circadian rhythm, and psychiatric disorders: Recent evidence and potential mechanisms

Abstract

The circadian rhythm is crucial for physiological and behavioral functions. Chronotype, which represents individual preferences for activity and performance, is associated with human health issues, particularly psychiatric disorders. This narrative review, which focuses on the relationship between chronotype and mental disorders, provides an insight into the potential mechanism. Recent evidence indicates that (1) the evening chronotype is a risk factor for depressive disorders and substance use disorders, whereas the morning chronotype is a protective factor. (2) Evening chronotype individuals with bipolar disorder tend to have more severe symptoms and comorbidities. (3) The evening chronotype is only related to anxiety symptoms. (4) The relationship between chronotype and schizophrenia remains unclear, despite increasing evidence on their link. (5) The evening chronotype is significantly associated with eating disorders, with the majority of studies have focused on binge eating disorders. Furthermore, the underlying mechanisms or influence factors are described in detail, including clock genes, brain characteristics, neuroendocrinology, the light/dark cycle, social factors, psychological factors, and sleep disorders. These findings provide the latest evidence on chronotypes and psychiatric disorders and serve as a valuable reference for researchers.

Genetically mediated associations between chronotype and neuroimaging phenotypes in the UK Biobank: a Mendelian randomisation study

“…There is mixed evidence for supporting a direct association with anxiety and an evening chronotype compared to depression and substance dependence [60], and the directionality of this relationship remains in question. Co-morbidity between substance abuse, including heavy alcohol intake, and mood disorders may introduce mediators of their individual relationships to chronotype [61]; and substance use may serve as a social zeitgeber influencing circadian preference. Obesity and cardiometabolic traits are also show a bi-directional relationship with chronotype; with evening chronotype individuals having a higher body mass index (BMI), ghrelin (hunger hormone) levels, and more unhealthy social eating patterns ¡Erim 2023¿.…”

Circadian Disruption and Mental Health: The Chronotherapeutic Potential of Microbiome-Based and Dietary Strategies

“…Circadian rhythmicity has recently started to garner great attention in neuroscience and psychiatry due to its impact on cognition, mood, and behavior. Moreover, the evening chronotype, commonly linked to circadian misalignment, has been described as a risk factor for more severe psychiatric symptoms and metabolic psychiatric comorbidities [29]. Impaired circadian rhythms, such as non-regular eating patterns and sleep disturbances, are commonly observed among individuals with various psychiatric disorders, including major depressive disorder (MDD), bipolar disorder (BD), anxiety, schizophrenia (SCZ), autism spectrum disorders (ASD), and attention deficit hyperactivity disorder (ADHD) [30].…”

Advances in the pathophysiology of bipolar disorder

“…More recently, Ritter et al [37 ▪▪ ] described that melatonin suppression by monochromatic blue light or monochromatic red light and differences in melatonin concentrations during dark conditions did not differ between euthymic patients with BD-I and healthy controls, suggesting that the circadian mediating mechanism is unlikely to be related to increased melatonin suppression by melanopsin-weighted light. Moreover, the evening BD chronotype is a higher risk factor for depressive disorders and substance use disorders, while the morning chronotype is a protective factor [38 ▪ ]. Furthermore, studies have also suggested that increased inflammatory cytokines may follow a circadian pattern, while inflammatory cytokines can disrupt spontaneous electrical activity rhythms in the suprachiasmatic nucleus [39].…”