The purpose of this study is to evaluate the feasibility of a multicentre, randomized, trial of light therapy and negative ion therapy as substitutes for antidepressants for maintenance treatment for patients with recurrent major depressive disorder (MDD).~The study design for this feasibility study mirrors the full LIMIT-D protocol: a 28-week, double-blind (participant and outcome rater) relapse prevention study with 100 participants randomized 1:1 to one of two study treatments, light therapy or negative ion therapy, and assessed for relapse over 28 weeks. Half the study devices are modified to be inactive. After 2 weeks of study treatment, the participant's antidepressant will be tapered and discontinued between Week 2 and Week 8.~Participants are assessed for relapse at each scheduled study visit (every 2 weeks during antidepressant taper until week 8, then every 4 weeks until end of study treatment at Week 28) by blind outcome raters. In addition, they complete an online Personal Health Questionnaire (PHQ-9) self-rated depression symptom scale weekly; if total score is 10 or higher OR the suicide item score is 2 or higher, participants are booked for a relapse-assessment visit and relapse-verification study visit at least 1 week apart. Relapse will be defined as any of the following:~MADRS total score 20 or higher for at least 2 consecutive weeks and Diagnostic and Statistical Manual (DSM-5) criteria for major depressive episode at the Relapse-Verification visit.~Hospitalization for worsening of depression.~Suicidal ideation with intent or plan, or suicidal behaviour.~Any change in treatment for depression (e.g., starting an antidepressant).~At each visit, clinician-rated and self-rated symptom, side effect, and functioning measures are completed. The primary feasibility outcome is recruitment rate; secondary feasibility outcomes include adherence to study treatment, successful discontinuation of antidepressants rate, and all-cause dropout rate. Secondary clinical outcomes include relapse rate, time to relapse, adverse events, and safety profiles.~Participants will wear an actigraph at home during the 28-week study treatment period to assess sleep, light and activity/circadian rhythms. There is a final observational visit by Zoom videoconference at Week 52.
Antidepressants are widely used as first-line treatments for major depressive disorder (MDD). Clinical guidelines recommend 6-24 months of maintenance antidepressant treatment, after patients achieve symptom remission, to prevent relapse but many people stop antidepressants too soon relapse into another depressive episode. We will test non-medication treatments, negative ion therapy and light therapy, to see they can substitute for antidepressants to prevent relapse. This is a feasibility study to see if participants use study treatments properly, before doing a larger, definitive trial. In this 28-week study, 100 participants with recurrent MDD who are in remission with antidepressants will be treated with light therapy or negative ion therapy (with half of devices active and half inactive) while slowly discontinuing the antidepressant, and monitored for relapse.