A randomized controlled trial with bright light and melatonin for the treatment of delayed sleep phase disorder: effects on subjective and objective sleepiness and cognitive function.
Study Goal
The researchers aimed to evaluate the short- and long-term effects of bright light and melatonin treatment, including dim light as a placebo, on sleepiness, fatigue, and cognitive function in individuals with delayed sleep phase disorder (DSPD).
Results Summary
In the short-term study, all treatments (including dim light placebo) improved subjective daytime sleepiness, fatigue, and cognitive function similarly. Long-term combined bright light and melatonin treatment maintained these benefits, while the no-treatment group reverted to baseline.
Population
Adolescents and young adults with delayed sleep phase disorder (DSPD).
Effective Dosage
Not specified for dim light (placebo).
Duration
Short-term (2 weeks), long-term (3 months).
Interactions
None mentioned.
| Intervention | Direction | Endpoint | Population | Dosage | Impact | Claim # |
|---|---|---|---|---|---|---|
gradual advancement of rise times | decrease | subjective sleepiness, fatigue, and cognitive performance | patients with DSPD | - | seems to produce positive effects | #1 |
all treatment conditions (bright light, melatonin, combination, and placebo) | decrease | subjective daytime sleepiness, fatigue, and cognitive function | - | - | were almost equally effective in improving | #2 |
2-week intervention | no change | objective sleepiness | - | - | showed no effect on | #3 |
Long-term treatment | increase | - | - | - | increased some of the positive effects | #4 |
combined bright light and melatonin treatment | decrease | subjective daytime sleepiness, fatigue, and cognitive function | - | - | improved | #5 |
no-treatment group | no change | most variables | - | - | returned to baseline values | #6 |
continuation of bright light and melatonin treatment | neutral | - | - | - | is beneficial to maintain positive effects | #7 |
Delayed sleep phase disorder (DSPD) is a circadian rhythm sleep disorder. Patients with DSPD have problems initiating sleep if they go to bed at a conventional time, and they often have problems waking at desired times. If they rise early in the morning, they usually experience severe sleepiness during morning hours. In the present study, we investigated the short- and long-term effects on measures of subjective and objective sleepiness and cognitive function of bright light and melatonin treatment alongside gradually advanced rise times in adolescents and young adults. Four treatment conditions were used in the short-term intervention (2 weeks): dim light (placebo) + placebo capsule, bright light + placebo capsule, dim light (placebo) + melatonin capsule, and bright light + melatonin capsule. This was followed by a long-term intervention (3 months) including 2 conditions: no treatment and combined bright light + melatonin treatment. Effects of treatment on sleepiness and fatigue were the primary outcome measures, and effects on cognitive function were secondary outcome measures. On a gradual advancement of the rise time schedule, all treatment conditions (bright light, melatonin, combination, and placebo) were almost equally effective in improving subjective daytime sleepiness, fatigue, and cognitive function in the 2-week study. The 2-week intervention showed no effect on objective sleepiness. Long-term treatment increased some of the positive effects seen after 2 weeks. The combined bright light and melatonin treatment improved subjective daytime sleepiness, fatigue, and cognitive function in the 3-month study. The no-treatment group returned to baseline values on most variables. In conclusion, a gradual advancement of rise times seems to produce positive effects on subjective sleepiness, fatigue, and cognitive performance during short-term treatment of patients with DSPD. However, the benefits from gradually advanced rise times seem to wear off, suggesting that the continuation of bright light and melatonin treatment is beneficial to maintain positive effects over time.