Volume 30, Issue 170, April 2026

Circadian Dysregulation in Bipolar Disorder and Schizophrenia

Anita Szymańska^1♦, Paulina Malon², Aleksandra Trojańska³, Anita Pieńkowska⁴, Karol Śliwa⁵, Nel Geworkian³, Natalia Hariasz⁶, Martyna Pietz³

¹Independent Physician, Poznań, Poland
²Nicolaus Copernicus University in Toruń, Collegium Medicum; Bydgoszcz 85-067, Poland
³University Clinical Hospital in Poznań, Przybyszewskiego 49; 60-355 Poznań, Poland
⁴Independent Physician, Białystok, Poland
⁵University of Warmia and Mazury in Olsztyn, Collegium Medicum; ul. Oczapowskiego 2, 10-719 Olsztyn, Poland
⁶4th Military Clinical Hospital in Wroclaw; Rudolfa Weigla 5, 50-981 Wrocław, Poland

^♦Corresponding author
Anita Szymańska, Independent Physician, Poznań, Poland

ABSTRACT

Sleep and circadian rhythms are fundamental to the proper functioning of emotions, cognitive processes, and behaviors. Dysregulations in those rhythms are a core feature of severe mental illnesses, particularly bipolar disorder (BP) and schizophrenia (SZ). Moreover, diverse changes in sleep architecture have been consistently reported throughout various illness stages and are associated with symptom severity, relapse risk, cognitive impairment, and psychosocial functioning. This review attempts to aggregate existing evidence on circadian rhythm disruption and sleep abnormalities in BP and SZ. It focuses on shared and disorder-specific mechanisms, clinical correlates, and therapeutic implications. The authors searched the literature using PubMed and Scopus, including papers published mainly in the last decade. Sleep patterns in those two disorders are not identical, but there are overlapping biological pathways, such as dysregulation of clock genes, neurohormonal alterations, and dopaminergic transmission. In this review, the authors will also discuss interventions targeting circadian rhythms, such as melatonin, chronotherapy, light-based interventions, and digitally supported monitoring. Studying the impact of circadian dysregulation on SZ and BP can support early detection, monitoring, and treatment for patients with those disorders.

Keywords: circadian rhythm; sleep disturbances; bipolar disorder; schizophrenia; chronobiology

Medical Science, 2026, 30, e77ms3823

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DOI: https://doi.org/10.54905/disssi.v30i170.e77ms3823

Published: 21 April 2026