Effectiveness of Light Therapy Across Seasons
18 mai 2026 mis à jour par: Claudia Simons, Geestelijke Gezondheidszorg Eindhoven (GGzE)
Is the Antidepressant Effect of Light Therapy for People With a Depressive Disorder Comparable in the Spring/Summer vs Autumn/Winter?
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.
Aperçu de l'étude
Statut
Complété
Intervention / Traitement
Type d'étude
Observationnel
Inscription (Réel)
212
Contacts et emplacements
Cette section fournit les coordonnées de ceux qui mènent l'étude et des informations sur le lieu où cette étude est menée.
Lieux d'étude
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Eindhoven, Pays-Bas, 5626ND
- GGzE
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Critères de participation
Les chercheurs recherchent des personnes qui correspondent à une certaine description, appelée critères d'éligibilité. Certains exemples de ces critères sont l'état de santé général d'une personne ou des traitements antérieurs.
Critère d'éligibilité
Âges éligibles pour étudier
- Adulte
- Adulte plus âgé
Accepte les volontaires sains
Non
Méthode d'échantillonnage
Échantillon non probabiliste
Population étudiée
The study population consists of patients with depression who are referred for treatment of depressive symptoms within a mental health care setting (GGzE, Eindhoven, The Netherlands), where bright light therapy is offered in a structured "Light Café" environment as part of routine clinical care.
La description
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 melatonin or short-term agomelatine use before starting light therapy
Plan d'étude
Cette section fournit des détails sur le plan d'étude, y compris la façon dont l'étude est conçue et ce que l'étude mesure.
Comment l'étude est-elle conçue ?
Détails de conception
Cohortes et interventions
Groupe / Cohorte |
Intervention / Traitement |
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Spring/summer
Patients with a depression who received bright light therapy as part of routine clinical care.
For the purpose of the analyses, participants were categorized based on the season of treatment initiation, with this cohort including those who started treatment during the spring and summer seasons.
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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).
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Autumn/winter
Patients with a depression who received bright light therapy as part of routine clinical care.
For the purpose of the analyses, participants were categorized based on the season of treatment initiation, with this cohort including those who started treatment during the autumn and winter seasons.
|
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).
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Que mesure l'étude ?
Principaux critères de jugement
Mesure des résultats |
Description de la mesure |
Délai |
|---|---|---|
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Change in depressive symptom severity (QIDS-SR)
Délai: Baseline to end of treatment (approximately 1-3 weeks after initiation of light therapy)
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Depressive symptom severity is assessed using the Quick Inventory of Depressive Symptomatology - Self-Report (QIDS-SR), a validated 16-item questionnaire with total scores ranging from 0 to 27 (higher scores indicating greater symptom severity).
The primary outcome is the change in QIDS-SR score from baseline (pre-treatment) to end of light therapy.
The analysis compares changes between participants treated in the spring/summer season and those treated in the autumn/winter season, while accounting for the delayed-start control condition.
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Baseline to end of treatment (approximately 1-3 weeks after initiation of light therapy)
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Mesures de résultats secondaires
Mesure des résultats |
Description de la mesure |
Délai |
|---|---|---|
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Sustained change in depressive symptoms (QIDS-SR follow-up)
Délai: End of treatment to 6 weeks and 3 months post-treatment
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Depressive symptom severity is assessed using the Quick Inventory of Depressive Symptomatology - Self-Report (QIDS-SR), a validated 16-item questionnaire with total scores ranging from 0 to 27 (higher scores indicating greater symptom severity).
This secondary outcome evaluates the persistence of treatment effects by comparing post-treatment scores to follow-up scores.
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End of treatment to 6 weeks and 3 months post-treatment
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Change in sleep quality (PSQI)
Délai: Baseline to 6 weeks and 3 months post-treatment
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Sleep quality is measured using the Pittsburgh Sleep Quality Index (PSQI), a validated self-report questionnaire with total scores ranging from 0 to 21 (higher scores indicating poorer sleep quality).
The outcome reflects change in sleep quality following light therapy.
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Baseline to 6 weeks and 3 months post-treatment
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Chronotype (MEQ)
Délai: Baseline (chronotype assessment), end of treatment (1-3 weeks after initiation of light therapy), 6 weeks post-treatment, and 3 months post-treatment
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Chronotype is assessed using the Morningness-Eveningness Questionnaire (MEQ).
This outcome examines whether baseline chronotype moderates changes in depressive symptom severity following light therapy.
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Baseline (chronotype assessment), end of treatment (1-3 weeks after initiation of light therapy), 6 weeks post-treatment, and 3 months post-treatment
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Adverse Events and Side Effects
Délai: At the end of each treatment week, up to 3 weeks
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Side effects are assessed using a self-report questionnaire capturing the presence and severity of common light therapy-related symptoms (e.g., headache, eye irritation, sleep disturbances).
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At the end of each treatment week, up to 3 weeks
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Change in Sleep-Wake Pattern during treatment
Délai: Twice weekly during treatment, up to 3 weeks
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Sleep timing, duration, quality and fragmentation, are assessed using a shortened sleep diary based on the Consensus Sleep Diary.
This outcome evaluates changes in sleep patterns during light therapy and their relation to treatment response.
Participants completed the diaries in the clinic on Mondays and Fridays, reporting retrospectively on their sleep during the preceding nights (i.e., Friday-Sunday nights for Monday entries and Monday-Thursday nights for Friday entries).
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Twice weekly during treatment, up to 3 weeks
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Collaborateurs et enquêteurs
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Dates d'enregistrement des études
Ces dates suivent la progression des dossiers d'étude et des soumissions de résultats sommaires à ClinicalTrials.gov. Les dossiers d'étude et les résultats rapportés sont examinés par la Bibliothèque nationale de médecine (NLM) pour s'assurer qu'ils répondent à des normes de contrôle de qualité spécifiques avant d'être publiés sur le site Web public.
Dates principales de l'étude
Début de l'étude (Réel)
1 janvier 2021
Achèvement primaire (Réel)
7 octobre 2022
Achèvement de l'étude (Réel)
23 décembre 2022
Dates d'inscription aux études
Première soumission
12 mai 2026
Première soumission répondant aux critères de contrôle qualité
18 mai 2026
Première publication (Réel)
20 mai 2026
Mises à jour des dossiers d'étude
Dernière mise à jour publiée (Réel)
20 mai 2026
Dernière mise à jour soumise répondant aux critères de contrôle qualité
18 mai 2026
Dernière vérification
1 mai 2026
Plus d'information
Termes liés à cette étude
Termes MeSH pertinents supplémentaires
Autres numéros d'identification d'étude
- ILB/2020038
Plan pour les données individuelles des participants (IPD)
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NON
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