Perinatal photoperiod associations with bipolar disorder and depression: A systematic literature review and cross-sectional analysis of the UK Biobank database

• Published in: Psychiatry research 2024-05, Vol.335, p.115878, Article 115878
• Main Authors: Lewis, Philip, Gottlieb, John F., Morfeld, Peter, Hellmich, Martin, Erren, Thomas C.
• Format: Article
• Language: English
• Subjects: Affective; Circadian; Developmental; Mood; Psychiatric; Season; Sunlight
• ISSN: 0165-1781; 1872-7123; 1872-7123
• DOI: 10.1016/j.psychres.2024.115878

•Perinatal photoperiod associations with bipolar and depression disorders are novel.•Associations were observed in the extensive UK Biobank database.•Findings are compatible with season of birth and depression studies.•Perinatal photoperiod may reconcile inconsistencies in season of birth studies.•Findings build on previous research by ourselves and other groups.•More extreme photoperiods need to be accounted for.•If associations are true, the door is opened to simple preventive strategies. Season-of-birth associations with psychiatric disorders point to environmental (co-)aetiological factors such as natural photoperiod that, if clarified, may allow interventions toward prevention. We systematically reviewed the literature concerning season-of-birth and bipolar disorder and depression and explored associations between the perinatal natural photoperiod and these outcomes in a cross-sectional analysis of the UK Biobank database. We used mean daily photoperiod and relative photoperiod range (relative to the mean) in the 3rd trimester and, separately, in the first 3 months post birth as metrics. From review, increased risk of depression with late spring birth is compatible with increased odds of probable single episode-, probable recurrent-, and diagnosed depression (OR 2.85 95 %CI 1.6–5.08, OR 2.20 95 %CI 1.57–3.1, and OR 1.48 95 %CI 1.11–1.97, respectively) with increasing 3rd trimester relative photoperiod range for participants who experienced relatively non-extreme daily photoperiods. Risk of bipolar disorder with winter-spring birth contrasted with no consistent patterns of perinatal photoperiod metric associations with bipolar disorder in the UK Biobank. As natural photoperiod varies by both time-of-year and latitude, perinatal natural photoperiods (and a hypothesized mechanism of action via the circadian timing system and/or serotonergic circuitry associated with the dorsal raphe nucleus) may reconcile inconsistencies in season-of-birth associations. Further studies are warranted.