A Circadian Medicine Light-Based Intervention for Obsessive-Compulsive Disorder
2022 Focused Projects Grant for Junior Investigators
Rebecca C. Cox, PhD
University of Colorado Boulder
Key Project Outcome
Despite established first-line treatments for obsessive-compulsive disorder (OCD), only 40% of those treated achieve remission, suggesting the presence of untreated mechanistic factors. One such factor may be delayed circadian rhythms, as there is evidence for circadian delay in OCD, including later chronotype, later circadian melatonin phase, and high comorbidity with delayed sleep-wake phase disorder. Thus, delayed circadian rhythms may represent a novel treatment target.
We examined the efficacy of light therapy, including increased morning light and decreased evening light, for reducing symptoms of OCD. This pilot randomized controlled trial included 20 participants with OCD who completed 3 weeks of active or sham light therapy delivered via wearable light therapy glasses for 1 hour after waking up in the morning. Those in the active condition were also instructed to reduce evening light exposure by being in dim light for 2 hours prior to bedtime. Participants who received active light therapy reported larger reduction in OCD symptoms than those in the sham condition, with the largest effect observed for reductions in intrusive thoughts. Participants who received active light therapy also demonstrated a 49- minute shift earlier in their sleep timing.
Our findings show that specifically targeting circadian rhythms results in reductions in OCD symptoms. Circadian medicine, such as light therapy, may be a useful adjunctive treatment to existing first-line treatments for OCD with the potential to improve treatment outcomes.