An intricate relationship between circadian rhythm dysfunction and psychiatric diseases

There is a complex relationship between circadian rhythm dysfunctions and various psychiatric disorders. Circadian (~24 h) rhythms indicate the rhythmic change of different physiological activities in relation to the environmental light-dark cycle. Shift work, light exposure at night, and chronic and acute jet lag affect circadian rhythm that have a negative impact on psychological functions, and behaviors. Additionally, professional stress, mental instability, and social disintegration influence psychiatric disorders. PubMed/MEDLINE, Springer Nature, Science Direct (Elsevier), Wiley Online, ResearchGate, and Google Scholar databases were searched to collect relevant articles. Circadian rhythm disruption causes impaired neurotransmitter release, impaired melatonin and cortisol rhythm, metabolic dysfunctions, neuroinflammation, and neural apoptosis; collectively these factors influence the development of psychiatric disorders. Circadian dysfunction also alters the expression of several clock control genes in the mesolimbic areas that are associated with pathologies of psychiatric disorders. Additionally, chronotherapy and applications of anti-psychotic medicine can improve psychiatric diseases. This review focuses on the effects of circadian clock dysfunction on the vulnerability of psychiatric disorders and the implications of chronotherapy.