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Effectiveness of Light Therapy Across Seasons

NCT07599124 · Status: COMPLETED · Type: OBSERVATIONAL · Enrollment: 212

Last updated 2026-05-20

No results posted yet for this study

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.

Conditions

  • Depression
  • Unipolar Depression
  • Bipolar Depression Depressed Phase

Interventions

DEVICE

Bright Light Therapy

Bright Light Therapy (BLT) will be administered according to Dutch depression guidelines, using Innolux LED light lamp (3800K, 10,000 lux). BLT will be given for one work week (Mon-Fri), 7:30-10:30 AM, 30 mins/session. Patients can have breakfast, read, or use devices. Treatment effectiveness will be evaluated using Self-Rated Quick Inventory of Depressive Symptoms (QIDS-SR). If remission is achieved (QIDS-SR \< 6), no additional treatment is given. If response is insufficient (QIDS-SR ≥ 6), 5 more sessions will be added in the following week, with maximum two extensions (1-3 weeks total).

Sponsors & Collaborators

  • Geestelijke Gezondheidszorg Eindhoven (GGzE)

    lead OTHER

Eligibility

Min Age
18 Years
Sex
ALL
Healthy Volunteers
No

Timeline & Regulatory

Start
2021-01-01
Primary Completion
2022-10-07
Completion
2022-12-23

Countries

  • Netherlands

Study Locations

More Related Trials

Entities

Diseases

Read the full study record

This page highlights key information. For complete eligibility criteria, study locations, investigator contacts, and the full protocol, visit the original record on ClinicalTrials.gov.

View NCT07599124 on ClinicalTrials.gov