Association between light exposure at night and manic symptoms in bipolar disorder: cross-sectional analysis of the APPLE cohort |
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Authors: | Yuichi Esaki Kenji Obayashi Keigo Saeki Kiyoshi Fujita Nakao Iwata Tsuyoshi Kitajima |
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Institution: | 1. Department of Psychiatry, Okehazama Hospital , Aichi, Japan;2. Department of Psychiatry, Fujita Health University School of Medicine , Aichi, Japan esakiz@fujita-hu.ac.jp;4. Department of Epidemiology, Nara Medical University School of Medicine , Nara, Japan https://orcid.org/0000-0001-6346-9082;5. Department of Epidemiology, Nara Medical University School of Medicine , Nara, Japan;6. Department of Psychiatry, The Neuroscience Research Center , Aichi, Japan;7. Department of Psychiatry, Fujita Health University School of Medicine , Aichi, Japan |
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Abstract: | ABSTRACT Previous studies have found that keeping the room dark at night was associated with a decrease in manic symptoms for patients with bipolar disorder (BD). However, the association between light at night of real-life conditions and manic symptoms is unclear. We investigated the association between bedroom light exposure at night and manic symptoms in BD patients. One-hundred and eighty-four outpatients with BD participated in this cross-sectional study. The average light intensity at night during sleep was evaluated using a portable photometer for seven consecutive nights. Manic symptoms were assessed using the Young Mania Rating Scale (YMRS), and scores ≥5 were treated as a “hypomanic state.” The median (interquartile range) YMRS score was 2.0 (0–5.0), and 52 (28.2%) participants were in a hypomanic state. The prevalence of a hypomanic state was significantly higher in the participants with an average light intensity at night exposure of ≥3 lux than in those with <3 lux (36.7% versus 21.9%; P = .02). In multivariable logistic regression analysis adjusted for BD type, depressive symptoms, sleep duration, and daytime physical activity, the odds ratio (OR) for a hypomanic state was significantly higher for the participants with an average light intensity at night exposure of ≥3 lux than for those with <3 lux (OR: 2.15, 95% confidence interval: 1.09–4.22, P = .02). This association remained significant at the cutoff value of YMRS score ≥6 (OR: 2.51, 95% confidence interval: 1.15–5.46; P = .02). The findings of this study indicate bedroom light exposure at night is significantly associated with manic symptoms in BD patients. Although the results of this cross-sectional investigation do not necessarily imply causality, they may serve to inform beneficial nonpharmacological intervention and personalized treatment of BD patients. |
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Keywords: | Bipolar disorder manic symptom light at night dark circadian rhythm |
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