Effects of Season on Melatonin Secretion in Healthy Men and Women and Patients With Seasonal Affective Disorder
Public ClinicalTrials.gov record NCT00001485. Field values are reproduced from the official study page; the official ClinicalTrials.gov record remains the source of truth for eligibility, enrollment, and contact information.
Data is sourced from official ClinicalTrials.gov public API records. Always review the official ClinicalTrials.gov record for the latest information.
Official title
Gender Differences in the Effects of Season on Patterns of Nocturnal Melatonin Secretion in Healthy Volunteers and Patients With Seasonal Affective Disorder (SAD)
Brief summary
Reproduced verbatim from the official ClinicalTrials.gov record. Not medical advice.
As the seasons change during the course of the year, many animals show major changes in their behavior and physiology. Many of these changes are triggered by changes in the length of time each night that the pineal gland produces the hormone melatonin. Melatonin is produced for a longer time in winter when nights are long, than in summer when nights are short. Some researchers believe that melatonin may play a similar role in how season effects mood of patients with seasonal affective disorder. Seasonal affective disorder (SAD) or mood disorder with seasonal pattern is a condition where the normal biorhythm is disturbed during a season, especially autumn-winter. Patients may begin experiencing or experience worsening of depressive symptoms. Patients complain of being constantly tired, craving sugary foods, overeating, and over sleeping. Researchers have collected some preliminary data showing that the duration of nighttime melatonin secretion increases in winter and decreases in summer in healthy women, but not in healthy men. However, men diagnosed with SAD have shown longer duration of melatonin secretion in the winter, similar to the duration seen in healthy women. If these early findings are confirmed it may explain why SAD is more common in women than in men. The purpose of this study is to continue researching the differences in melatonin secretion over the seasons in healthy men and women, and to determine how these findings may apply to patients with SAD.
Study identification
- NCT ID
- NCT00001485
- Recruitment status
- Completed
- Study type
- Observational
- Phase
- Not listed
- Enrollment
- 116 participants
Conditions and interventions
Conditions
Interventions
Not listed
Eligibility (public fields only)
- Age range
- Not listed
- Sex
- All
- Healthy volunteers
- Accepts healthy volunteers
This page does not interpret eligibility. Detailed inclusion and exclusion criteria are on the official ClinicalTrials.gov record.
Study timeline
- Start date
- May 31, 1995
- Primary completion
- Not listed
- Completion
- Mar 31, 2000
- Last update posted
- Mar 3, 2008
1995 – 2000
United States locations
- U.S. sites
- 1
- U.S. states
- 1
- U.S. cities
- 1
| Facility | City | State | ZIP | Site status |
|---|---|---|---|---|
| National Institute of Mental Health (NIMH) | Bethesda | Maryland | 20892 | — |
Site contact phone numbers, emails, and investigator names are intentionally not displayed here. Open the official ClinicalTrials.gov record for site contact information.
About this trial record page
- What this page shows
- Public field values for ClinicalTrials.gov record NCT00001485, including study identification, conditions, interventions, eligibility (age, sex, healthy volunteer), timeline, and U.S. site list.
- What this page does not do
- No medical advice, eligibility judgments, treatment recommendations, study quality scoring, or AI-generated medical summaries. No site contact phone numbers, emails, or investigator names.
- Where the data comes from
- Sourced from the official ClinicalTrials.gov public API. The official record is the source of truth.
- Last refresh
- Last update posted Mar 3, 2008 · Synced Sep 13, 2026
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Open the official record
The complete protocol, eligibility criteria, and contact information for NCT00001485 live on ClinicalTrials.gov.