This small pilot study looked at adults aged 19 to 64 with ADHD from an outpatient psychiatry clinic. Most kept taking their usual stimulant medication in the morning. People with other psychiatric conditions, sleep apnea, eye disorders, light-sensitive skin or shift work were not included. The paper's counts do not fully agree, but 16 people had body clock data that could be analyzed.
After one baseline week, participants used a 10,000-lux light box at home for 30 minutes a day for two weeks. The timing was set 3 hours after each person's midpoint of sleep. They were also asked to limit overhead light and wear blue-blocking glasses outside after 4 p.m. On average, people used the box on about 10 of the 14 days.
The evening rise in melatonin came 31 minutes earlier, and the middle of sleep came 57 minutes earlier. Both shifts were unlikely to be down to chance. People whose body clock shifted more tended to have larger drops in ADHD symptom scores, especially hyperactive and impulsive symptoms. Sleepiness and sleep quality ratings improved. In a group of 8 who wore movement trackers, total sleep time and sleep efficiency did not change significantly.
There was no comparison group, and the sample was small. The authors present timed morning bright light as a feasible, possibly complementary treatment for delayed sleep timing and ADHD symptoms in adults like these, and say a randomized, placebo-controlled trial is needed.
Talk to a clinician about your own situation.
The numbers Stats and what the terms mean
The statistics behind the plain-language claims above.
- Fargason, 2017: timing of the evening melatonin rise (DLMO) before and after light therapy, mean time (SEM) 20:36 (0:21) to 20:05 (0:20), p = 0.002.
- Fargason, 2017: timing of the middle of sleep before and after light therapy, 4:37 (0:22) to 3:40 (0:16), p = 0.004.
- Fargason, 2017: link between the earlier melatonin rise or earlier mid-sleep and lower total ADHD symptom scores (as given in the abstract), p = 0.027 and 0.044.
- Fargason, 2017: link between the earlier melatonin rise or earlier mid-sleep and lower hyperactive-impulsive scores (as given in the abstract), p = 0.014 and 0.013.
- Fargason, 2017: total sleep time in the tracker group of 8, 7.2 to 7.1 h, p = 0.677.
- Fargason, 2017: sleep efficiency in the tracker group of 8, 81.3% to 77.4%, p = 0.333.
- Fargason, 2017: sleep diary sleepiness ratings, 2.97 ± 0.13 to 2.63 ± 0.21 (mean ± SEM), p = 0.033.
- Fargason, 2017: sleep quality questionnaire (PSQI) score, 10.1 ± 1.2 to 6.1 ± 1.3, p < 0.001.
What the terms mean:
- Pilot study A small, early study run mainly to see whether a bigger study can work. This one tested light therapy in a small group of adults with ADHD.
- Control group The group in a study that does not get the thing being tested, so the other group has something to be compared with. This study had none.
- P-value A number from a statistical test that shows how unusual a result would be if there were really no effect, and it depends on the study's own assumptions being right.
- Statistical significance A label researchers give a result when its p-value falls below a cutoff set in advance, most often 0.05. It is a statistical term, not the everyday sense of important or big.
- DLMO Dim light melatonin onset, the time in the evening when the body starts making the sleep hormone melatonin in dim light, used here as a marker of body clock timing.
- SEM Standard error of the mean, a measure of how precisely the average was estimated.
- PSQI A sleep quality questionnaire. In this study, the drop in score was reported as an improvement.
Source: Fargason R, Fobian A, Hablitz L, et al.. Correcting delayed circadian phase with bright light therapy predicts improvement in ADHD symptoms: A pilot study. Journal of Psychiatric Research (2017). doi:10.1016/j.jpsychires.2017.03.004