A Wearable Morning Light Treatment for Postpartum Depression

This study will test a consumer health light therapy device (Re-Timer) for women with postpartum depression to better understand how it affects mood and the body clock (also called the circadian clock). Eligible participants will be enrolled and randomized after baseline assessments. In addition to using the Re-Timer light for 5 weeks participants will complete questionnaires at various timepoints, record sleep information, wear an actigraph watch, and provide saliva samples. Additionally, the sleep of the participants' infants will also be monitored using an ankle-worn device (actigraph) and sleep diary at certain time-points as this may influence the mother's mood/sleep, and in turn affect the results. The hypotheses regarding the bright light versus the placebo dim light of the study are: * morning bright light therapy will produce greater improvement from pre- to post-treatment on the Hamilton Rating Scale for Depression * morning bright light therapy will lengthen the Phase angle difference (PAD) and this will mediate change in depression symptoms. * morning bright light therapy will produce greater improvements on self-reported depression symptoms, excessive daytime sleepiness, maternal-infant bonding, social functioning, and sleep-related impairment from pre- to post-treatment.

Please note this project added a sub-study (HUM00235787, IRB approved on 7/31/2024) to the main study. However, the sub-study only applies to some of the participants and there are only exploratory outcomes, therefore, this will not affect the main study registration.