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Wescott, Delainey (2021) SLEEP AND CIRCADIAN PHENOTYPES IN SEASONAL DEPRESSION. Master's Thesis, University of Pittsburgh. (Unpublished)

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Background: Sleep and circadian rhythm disruptions have long been considered important symptoms and theorized underlying mechanisms in seasonal depression. However, discrepant observational findings and mixed treatment responses suggest heterogenous sleep and circadian disruptions in this population. This study aimed to elucidate distinct sleep and circadian profiles in seasonal depression to 1) clarify mixed findings of prior work and 2) identify modifiable treatment targets for future interventions.

Methods: Biobehavioral, prospective self-report, and retrospective self-report measures of sleep and circadian rhythms were assessed during the winter in individuals meeting diagnostic criteria for Seasonal Affective Disorder (SAD), subsyndromal-SAD (S-SAD), or nonseasonal, never depressed controls (N=196). Sleep and circadian measures included: circadian phase/chronotype, sleep timing, total sleep time, sleep efficiency, regularity, and daytime sleepiness. Three k-means cluster analyses were conducted for each measurement modality. Resulting cluster solutions were compared on demographics, depression severity, and sleep and circadian dimensions.

Results: There were two consistent sleep and circadian profiles across all three cluster analyses, an ‘Insomnia’ cluster, characterized by short total sleep times (<6.5 hours), irregular and fragmented sleep and an ‘Advanced’ cluster, characterized by early sleep and circadian timing and longer total sleep times (> 7.5 hours). A smaller cluster, ‘Nappers with long sleep’ cluster, was also identified in the biobehavioral cluster. Clusters did not differ on depression severity or stratify by diagnostic group. Despite marked differences between clusters, there were few sleep and circadian differences between diagnostic groups (controls, SAD, S-SAD). Retrospective clusters did not differ on chronotype or sleep timing.

Conclusion: The heterogeneity in seasonal depression is characterized by three sleep and circadian profiles with similar depression severity. Rather than assuming a homogenous sleep and circadian profile in seasonal depression, assessing sleep and circadian rhythms prior to treatment may reduce treatment failures. More broadly, this work highlights the utility of a precision medicine approach to treat sleep and circadian disruptions in individuals with dysregulated mood.


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Item Type: University of Pittsburgh ETD
Status: Unpublished
CreatorsEmailPitt UsernameORCID
Wescott, Delaineydlw92@pitt.edudlw92
ETD Committee:
TitleMemberEmail AddressPitt UsernameORCID
Committee ChairRoecklein,
Committee MemberHall,
Committee MemberWallace,
Date: 20 January 2021
Date Type: Publication
Defense Date: 9 November 2020
Approval Date: 20 January 2021
Submission Date: 27 November 2020
Access Restriction: No restriction; Release the ETD for access worldwide immediately.
Number of Pages: 78
Institution: University of Pittsburgh
Schools and Programs: Dietrich School of Arts and Sciences > Psychology
Degree: MS - Master of Science
Thesis Type: Master's Thesis
Refereed: Yes
Uncontrolled Keywords: sleep, circadian rhythms, seasonal depression, mood, hypersomnolence
Date Deposited: 20 Jan 2021 19:39
Last Modified: 20 Jan 2021 19:39

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  • SLEEP AND CIRCADIAN PHENOTYPES IN SEASONAL DEPRESSION. (deposited 20 Jan 2021 19:39) [Currently Displayed]


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