Light therapy as an add-on to standard care for perinatal depression: a 7-month follow-up randomized controlled study

Many women with perinatal depression (PND) do not respond adequately to treatment, and perinatal insomnia remains particularly challenging to manage. The aim of this study was to evaluate the efficacy of light therapy (LT) as an adjunctive treatment to standard care in reducing symptoms of PND and sleep disturbances.

Outcomes were compared with a control group of women with PND who received standard care alone. A final sample of 15 women (7 in the LT group and 8 in the non-LT group) was recruited at the "SOS MAMMA" clinic at the University of Rome "Tor Vergata." Participants in the LT group received 30 minutes of light therapy daily for five consecutive weeks. We performed a baseline clinical assessment, and the following psychometric instruments were administered from the T0, weekly for five weeks (T1-T5), after one months (T6): Edinburgh Postnatal Depression Scale (EPDS), Pittsburgh Sleep Quality Index (PSQI), Beck Depression Inventory-II (BDI-II), Hamilton Depression Rating Scale (HAM-D). LT group underwent a follow-up six months later (T7).

The repeated measures ANOVA showed statistically significant Time × Group interaction effects of all psychopathological outcomes. LT-group showed greater improvements of depressive symptoms (BDI-II: Wilks' λ= .281, F= 3.42, η2= .719, p= .056; HAM-D: Wilks' λ= .290, F= 3.27, η2= .710, p= .062; EPDS: Wilks' λ= .134, F= 8.61, η2= .866, p= .004) and sleep quality (PSQI: Wilks' λ= .302, F= 3.07, η2= .698, p= .072) compared to the non-LT group. In the LT-group, the paired-sample t-tests comparing T6 with T7 showed improvements of BDI-II (t, 6= 3.81; Cohen's d= 1.44; p= .009) and PSQI (t, 6= 3.10; Cohen's d= 1.17; p= .021), indicating that the effectiveness was maintained over time.

Light therapy proved effective as an augmentation treatment in women with perinatal depression, demonstrating sustained efficacy over time and strategic tolerability. We propose that LT is a valuable intervention that targets difficult-to-treat symptoms such as insomnia, and may allow for the use of lower doses of antidepressants - reducing concerns about potential adverse effects on the offspring.