CompletedNot Applicable

Effectiveness of Light Therapy Across Seasons

Netherlands212 participantsStarted 2021-01-01

Plain-language summary

This study investigates whether the antidepressant effects of bright light therapy (BLT) differ between the spring/summer season and the autumn/winter season in adults with depressive disorders. While BLT is an established treatment for seasonal affective disorder, increasing evidence suggests it may also be effective for non-seasonal depression. However, it remains unclear whether its effectiveness depends on seasonal variation in natural daylight exposure. In this prospective study conducted in a routine clinical care setting, patients referred for depressive symptoms and a score of \> 6 on the Quick Inventory of Depressive Symptomatology-Self-Report (QIDS-SR) receive BLT in a structured "Light Café" environment. Participants undergo daily morning light therapy sessions (30 minutes at 10,000 lux) for at least one week, with possible extension up to three weeks based on treatment response. A delayed-start design is used, where a subset of participants begins treatment two weeks later, allowing comparison with the natural course of depressive symptoms. Depressive symptoms are assessed using the QIDS-SR at baseline, during treatment, and at follow-up (6 weeks and 3 months post-treatment). Sleep quality, chronotype, circadian timing, and side effects are also measured. The primary objective is to compare the effectiveness of BLT across seasons. Secondary objectives include evaluating the persistence of treatment effects, assessing the change in sleep quality and day-to-day sleep-wake pattern, and exploring whether outcomes vary by chronotype, circadian phase, and patient characteristics. This study aims to inform whether BLT should be considered a year-round treatment option for depressive disorders and to better understand factors influencing individual treatment response.

Who can participate

Age range

18 Years

Sex

ALL

See this in plain English?

AI-rewrites the medical criteria so a patient or caregiver can understand them. Always confirm with the trial site.

Inclusion Criteria: * Adults aged 18 years or older * Diagnosis of a depressive disorder (unipolar or bipolar), including both seasonal and non-seasonal depression * Currently indicated for bright light therapy * QIDS-SR score ≥ 6 at baseline * Able to provide informed consent * Sufficient proficiency in Dutch or English to complete questionnaires Exclusion Criteria: * Current (hypo)manic or mixed episode * Current psychotic episode * Severe suicidal ideation requiring immediate intervention * Diagnosis of dementia * QIDS-SR score ≤ 5 at baseline * Age \< 18 years * Inability to provide informed consent * Insufficient language proficiency to complete study questionnaires * Initiation, dose change, or switch of antidepressant medication within 3 weeks before or during light therapy * Long-term use of agomelatine Relative Contraindications (require consultation with treating physician before participation): * Pregnancy (first trimester) * Diabetes or other systemic vascular diseases * Eye conditions associated with increased light sensitivity * Epilepsy Medication-Related Considerations: * Participants are advised not to start antibiotics during light therapy (existing courses should be completed prior to participation) * Participants are advised to discontinue use of photosensitizing medications or topical agents during treatment * Participants are asked to discontinue melatonin use during light therapy * A wash-out period of 1 month is required after discontinuation of…

Questions worth asking your doctor

Bring these to your next appointment. They're a starting point for a shared conversation — not a sign you qualify or a recommendation to enrol.

1This trial studied light therapy for depression across different seasons — does the time of year I'm starting treatment actually affect how well light therapy might work for my specific type of depression?
2The trial included both unipolar and bipolar depression — since those two conditions are treated very differently, how would my doctor interpret the results from this study for someone with my exact diagnosis?
3The trial measured changes using a self-reported depression scale called the QIDS-SR — what kind of symptom improvements were actually observed, and would my doctor consider those changes meaningful enough to affect my treatment plan?
4Since this trial is now completed, is the full data published or available anywhere, and does my doctor think the findings support adding light therapy to what I'm already doing?
5Given that this was a Phase NA observational or non-drug study, does my doctor think light therapy is ready to be considered as a real option for me right now, or would standard antidepressant treatment still be a better first step?

Generated to help you prepare — always confirm anything about your own eligibility and care with the study team and your doctor.

Questions for the trial coordinator

The trial coordinator is the person who runs the study day to day. These cover the practical side — logistics, costs, and what taking part would actually mean for your life. The study team confirms whether you meet the criteria; these are questions to ask, not a sign you qualify.

1What does taking part actually involve week to week — how many visits, where, and how long does each one take?
2What costs are covered by the study, and what might I have to pay for myself, including travel, parking, or time off work?
3What happens during screening, and what happens if the study team confirms I don't meet the criteria after those tests?
4Who pays for the scans, blood work, and other tests the trial requires — the study, my insurance, or me?
5How will being in the trial affect my regular care, and will my own doctor stay informed and involved?
6Can I leave the trial at any point if I change my mind, and what would happen to my care if I do?

A starting point for the conversation — always confirm anything about your own eligibility, costs, and care with the study team and your doctor.

What they're measuring

Change in depressive symptom severity (QIDS-SR)

Timeframe: Baseline to end of treatment (approximately 1-3 weeks after initiation of light therapy)

Trial details

NCT IDNCT07599124

SponsorGeestelijke Gezondheidszorg Eindhoven (GGzE)

Sponsor typeOTHER

Study typeOBSERVATIONAL

Primary completion2022-10-07

View on ClinicalTrials.gov More Depression trials