Efficacy of Chronotherapeutic Combination for Major Depressive Episode With Insomnia

Major Depressive Disorder (MDD) affects 5% of the global population and is the second leading cause of disability worldwide. Despite the widespread use of antidepressants, 50-60% of patients do not respond adequately after 8 weeks of treatment. Insomnia, present in approximately 85% of individuals with MDD, is a frequent and persistent symptom that contributes to poor treatment outcomes. Targeting insomnia has been shown to enhance both symptom remission and functional recovery. In this context, combined therapeutic strategies are often used to optimize the antidepressant response. Among them, chronotherapeutic approaches, such as light therapy and prolonged-release melatonin, have demonstrated rapid antidepressant effects and are beneficial in regulating sleep and circadian rhythms. Light therapy shows an efficacy comparable to antidepressants and, when used in combination with them, can double treatment effectiveness. Melatonin is also recommended in the management of depression-related insomnia. This multicenter, randomized, double-blind, placebo-controlled trial with a 2x2 factorial design aims to evaluate the efficacy of two chronotherapeutic interventions, 8 weeks of active light therapy and 2 mg of prolonged-release melatonin-administered alone or in combination, on depressive symptom reduction at 8 weeks in adult patients with MDD and comorbid insomnia. The primary outcome is the change in Montgomery-Åsberg Depression Rating Scale (MADRS) score from baseline to week 8. All participants will receive antidepressant treatment and sleep hygiene education. This study proposes a novel therapeutic strategy combining pharmacological and non-pharmacological interventions to address both depression and insomnia, with the goal of improving outcomes, especially for the 40% of patients who do not adequately respond to antidepressants alone.