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Effectiveness of Light Therapy Across Seasons

18 de mayo de 2026 actualizado por: 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.

Descripción general del estudio

Estado

Terminado

Condiciones

Intervención / Tratamiento

Tipo de estudio

De observación

Inscripción (Actual)

212

Contactos y Ubicaciones

Esta sección proporciona los datos de contacto de quienes realizan el estudio e información sobre dónde se lleva a cabo este estudio.

Ubicaciones de estudio

Criterios de participación

Los investigadores buscan personas que se ajusten a una determinada descripción, denominada criterio de elegibilidad. Algunos ejemplos de estos criterios son el estado de salud general de una persona o tratamientos previos.

Criterio de elegibilidad

Edades elegibles para estudiar

  • Adulto
  • Adulto Mayor

Acepta Voluntarios Saludables

No

Método de muestreo

Muestra no probabilística

Población de estudio

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.

Descripción

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 de estudios

Esta sección proporciona detalles del plan de estudio, incluido cómo está diseñado el estudio y qué mide el estudio.

¿Cómo está diseñado el estudio?

Detalles de diseño

Cohortes e Intervenciones

Grupo / Cohorte
Intervención / Tratamiento
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.
Dispositivo: 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).
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.
Dispositivo: 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).

¿Qué mide el estudio?

Medidas de resultado primarias

Medida de resultado
Medida Descripción
Periodo de tiempo
Change in depressive symptom severity (QIDS-SR)
Periodo de tiempo: Baseline to end of treatment (approximately 1-3 weeks after initiation of light therapy)
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.
Baseline to end of treatment (approximately 1-3 weeks after initiation of light therapy)

Medidas de resultado secundarias

Medida de resultado
Medida Descripción
Periodo de tiempo
Sustained change in depressive symptoms (QIDS-SR follow-up)
Periodo de tiempo: End of treatment to 6 weeks and 3 months post-treatment
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.
End of treatment to 6 weeks and 3 months post-treatment
Change in sleep quality (PSQI)
Periodo de tiempo: Baseline to 6 weeks and 3 months post-treatment
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.
Baseline to 6 weeks and 3 months post-treatment
Chronotype (MEQ)
Periodo de tiempo: Baseline (chronotype assessment), end of treatment (1-3 weeks after initiation of light therapy), 6 weeks post-treatment, and 3 months post-treatment
Chronotype is assessed using the Morningness-Eveningness Questionnaire (MEQ). This outcome examines whether baseline chronotype moderates changes in depressive symptom severity following light therapy.
Baseline (chronotype assessment), end of treatment (1-3 weeks after initiation of light therapy), 6 weeks post-treatment, and 3 months post-treatment
Adverse Events and Side Effects
Periodo de tiempo: At the end of each treatment week, up to 3 weeks
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).
At the end of each treatment week, up to 3 weeks
Change in Sleep-Wake Pattern during treatment
Periodo de tiempo: Twice weekly during treatment, up to 3 weeks
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).
Twice weekly during treatment, up to 3 weeks

Colaboradores e Investigadores

Aquí es donde encontrará personas y organizaciones involucradas en este estudio.

Patrocinador

Geestelijke Gezondheidszorg Eindhoven (GGzE)

Fechas de registro del estudio

Estas fechas rastrean el progreso del registro del estudio y los envíos de resultados resumidos a ClinicalTrials.gov. Los registros del estudio y los resultados informados son revisados ​​por la Biblioteca Nacional de Medicina (NLM) para asegurarse de que cumplan con los estándares de control de calidad específicos antes de publicarlos en el sitio web público.

Fechas importantes del estudio

Inicio del estudio (Actual)

1 de enero de 2021

Finalización primaria (Actual)

7 de octubre de 2022

Finalización del estudio (Actual)

23 de diciembre de 2022

Fechas de registro del estudio

Enviado por primera vez

12 de mayo de 2026

Primero enviado que cumplió con los criterios de control de calidad

18 de mayo de 2026

Publicado por primera vez (Actual)

20 de mayo de 2026

Actualizaciones de registros de estudio

Última actualización publicada (Actual)

20 de mayo de 2026

Última actualización enviada que cumplió con los criterios de control de calidad

18 de mayo de 2026

Última verificación

1 de mayo de 2026

Más información

Términos relacionados con este estudio

Palabras clave

Términos MeSH relevantes adicionales

Otros números de identificación del estudio

  • ILB/2020038

Plan de datos de participantes individuales (IPD)

¿Planea compartir datos de participantes individuales (IPD)?

NO

Esta información se obtuvo directamente del sitio web clinicaltrials.gov sin cambios. Si tiene alguna solicitud para cambiar, eliminar o actualizar los detalles de su estudio, comuníquese con register@clinicaltrials.gov. Tan pronto como se implemente un cambio en clinicaltrials.gov, también se actualizará automáticamente en nuestro sitio web. .

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