Department of Psychiatry, Okehazama Hospital, Aichi, Japan.
Department of Psychiatry, Fujita Health University School of Medicine, Aichi, Japan.
Acta Psychiatr Scand. 2021 Apr;143(4):328-338. doi: 10.1111/acps.13287. Epub 2021 Feb 23.
Light therapy has been suggested to have a curative effect on bipolar depression; however, preventive effects of light exposure on depressive episodes remain unclear. This study evaluated whether daytime light exposure in real-life situations was associated with a preventive effect on relapse into depressive episodes in patients with bipolar disorder.
This prospective, naturalistic, observational study was conducted in Japan between August 2017 and June 2020. Outpatients with bipolar disorder were objectively evaluated for daytime light exposure over 7 consecutive days using an actigraph that could measure ambient light at baseline assessment and then assessed at 12-month follow-up for relapse into mood episodes.
Of 202 participants, 198 (98%) completed follow-up at 12 months and 78 (38%) experienced relapse into depressive episodes during follow-up. In a Cox proportional hazards model adjusting for potential confounders, a longer time above 1000 lux at daytime was significantly associated with decrease in relapse into depressive episodes (per log min; hazard ratio, 0.66; 95% confidence interval, 0.50-0.91). In addition, a higher average illuminance and longer time above 1000 lux in the morning exhibited a significant decrease in relapse into depressive episodes (per log lux and per log min; hazard ratio, 0.65 and 0.61; 95% confidence interval, 0.49-0.86 and 0.47-0.78, respectively). The association between daytime light exposure and relapse into manic/hypomanic/mixed episodes was not significantly different.
A significant association was observed between increased daytime light exposure, mainly in the morning, and decreased relapse into depressive episodes.
光照疗法已被证明对双相抑郁具有疗效；然而，光照暴露对抑郁发作的预防作用尚不清楚。本研究评估了现实生活中白天的光照暴露是否与预防双相情感障碍患者抑郁发作复发有关。
本前瞻性、自然主义、观察性研究于 2017 年 8 月至 2020 年 6 月在日本进行。在基线评估时，使用能够测量环境光的活动记录仪客观评估 7 天内的日间光照暴露情况，然后在 12 个月随访时评估是否出现心境发作复发。
在 202 名参与者中，198 名（98%）在 12 个月时完成了随访，78 名（38%）在随访期间出现了抑郁发作复发。在调整潜在混杂因素的 Cox 比例风险模型中，白天超过 1000 勒克斯的时间更长与抑郁发作复发减少显著相关（每对数分钟；风险比，0.66；95%置信区间，0.50-0.91）。此外，早晨的平均照度较高和超过 1000 勒克斯的时间较长与抑郁发作复发减少显著相关（每对数勒克斯和每对数分钟；风险比，0.65 和 0.61；95%置信区间，0.49-0.86 和 0.47-0.78）。日间光照暴露与躁狂/轻躁狂/混合发作复发之间的关联无显著差异。
日间光照暴露增加，主要是在早晨，与抑郁发作复发减少显著相关。
