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Circadian depression: A mood disorder phenotype

Lookup NU author(s): Emeritus Professor Jan Scott


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© 2021Major mood syndromes are among the most common and disabling mental disorders. However, a lack of clear delineation of their underlying pathophysiological mechanisms is a major barrier to prevention and optimised treatments. Dysfunction of the 24-h circadian system is a candidate mechanism that has genetic, behavioural, and neurobiological links to mood syndromes. Here, we outline evidence for a new clinical phenotype, which we have called ‘circadian depression’. We propose that key clinical characteristics of circadian depression include disrupted 24-h sleep-wake cycles, reduced motor activity, low subjective energy, and weight gain. The illness course includes early age-of-onset, phenomena suggestive of bipolarity (defined by bidirectional associations between objective motor and subjective energy/mood states), poor response to conventional antidepressant medications, and concurrent cardiometabolic and inflammatory disturbances. Identifying this phenotype could be clinically valuable, as circadian-targeted strategies show promise for reducing depressive symptoms and stabilising illness course. Further investigation of underlying circadian disturbances in mood syndromes is needed to evaluate the clinical utility of this phenotype and guide the optimal use of circadian-targeted interventions.

Publication metadata

Author(s): Carpenter JS, Crouse JJ, Scott EM, Naismith SL, Wilson C, Scott J, Merikangas KR, Hickie IB

Publication type: Review

Publication status: Published

Journal: Neuroscience and Biobehavioral Reviews

Year: 2021

Volume: 126

Pages: 79-101

Print publication date: 01/07/2021

Online publication date: 06/03/2021

Acceptance date: 28/02/2021

ISSN (print): 0149-7634

ISSN (electronic): 1873-7528

Publisher: Elsevier Ltd


DOI: 10.1016/j.neubiorev.2021.02.045

PubMed id: 33689801