Department of Psychology, University of Pittsburgh; The Center for the Neural Basis of Cognition.
Department of Psychiatry, University of Pittsburgh School of Medicine, University of Pittsburgh, Pittsburgh, PA, United States.
J Affect Disord. 2021 Aug 1;291:93-101. doi: 10.1016/j.jad.2021.04.084. Epub 2021 May 2.
A retinal subsensitivity to environmental light may trigger Seasonal Affective Disorder (SAD) under low wintertime light conditions. The main aim of this study was to assess the responses of melanopsin-containing retinal ganglion cells in participants (N= 65) diagnosed with unipolar SAD compared to controls with no history of depression. Participants attended a summer visit, a winter visit, or both. Retinal responses to light were measured using the post-illumination pupil response (PIPR) to assess melanopsin-driven responses in the non-visual light input pathway. Linear mixed-effects modeling was used to test a groupseason interaction on the Net PIPR (red minus blue light response, percent baseline). We observed a significant groupseason interaction such that the PIPR decreased from summer to winter significantly in the SAD group while not in the control group. The SAD group PIPR was significantly lower in winter compared to controls but did not differ between groups in summer. Only 60% of the participants underwent an eye health exam, although all participants reported no history of retinal pathology, and eye exam status was neither associated with outcome nor different between groups. This seasonal variation in melanopsin driven non-visual responses to light may be a risk factor for SAD, and further highlights individual differences in responses to light for direct or indirect effects of light on mood.
视网膜对环境光的敏感性降低可能会在冬季光照条件较低时引发季节性情感障碍（SAD）。本研究的主要目的是评估与无抑郁病史的对照组相比，诊断为单相 SAD 的参与者（N=65）中含有黑视素的视网膜神经节细胞的反应。参与者参加了夏季访问、冬季访问或两者兼有。使用光后瞳孔反应（PIPR）来评估非视觉光输入途径中黑视素驱动的反应，以测量对光的视网膜反应。线性混合效应模型用于测试组季节交互作用对净 PIPR（红光减去蓝光反应，相对于基线的百分比）的影响。我们观察到一个显著的组季节交互作用，即 SAD 组的 PIPR 从夏季到冬季显著下降，而对照组则没有。SAD 组的 PIPR 在冬季明显低于对照组，但在夏季两组之间没有差异。尽管所有参与者均报告无视网膜病史，且眼部检查状况与结果无关且组间无差异，但只有 60%的参与者接受了眼部健康检查。这种光驱动的非视觉反应中黑视素的季节性变化可能是 SAD 的一个风险因素，进一步强调了对光的反应存在个体差异，可能是光对情绪的直接或间接影响。
