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Light Flashes Plus Cognitive Behavior Therapy Can Increase Teens' Sleep Time

October 04, 2019

By Marilynn Larkin

NEW YORK—Exposure to light flashes during sleep, combined with a brief cognitive behavior therapy (CBT) intervention, can increase total sleep time in teenagers, researchers say.

"Many teens don't get enough sleep. This is often caused by late bedtimes and early school start times," Dr. Jamie Zeitzer of the Stanford University School of Medicine told Reuters Health by email. "The latening of bedtimes is caused by a combination of biological (the circadian system signals for sleep are later) and behavioral (increased freedoms associated with light exposure) factors."

"The current therapy for the biological component is to get up before normal wake time and expose oneself to bright light - a difficult proposition for most teens, especially since it needs to be every day," he said.

"It is very difficult for CBT alone to help teens go to sleep early as there is a strong circadian drive for (staying awake) in the hours before normal bedtime," he explained. "We wanted to test if we could give light flashes during sleep that would not wake the teen, yet still impact the circadian system, moving it to an earlier hour."

"When we gave light flashes alone, teens got sleepier earlier, but did not go to sleep earlier," he noted. "When we gave CBT alone, the teens had a difficult time maintaining a regular earlier bedtime and ended up not getting much extra sleep."

"When we combined the two, however, we were able to get the extra 43 minutes of sleep per night," he said.

Dr. Zeitzer and colleagues randomly assigned 102 teens (mean age, 15.6 years; about half girls) who had difficulty going to bed earlier and waking up early enough to an intervention of sham therapy group. The trial was conducted in two phases.

In phase one, 72 participants were assigned to receive either three weeks of light or sham therapy, and were asked to try to go to sleep earlier. In phase two, 30 participants received four brief CBT sessions in addition to a modified light or sham therapy.

Light therapy consisted of receiving a 3-millisecond light flash every 20 seconds during the final three hours of sleep (phase 1) or final two hours of sleep (phase 2) every night for four weeks. CBT consisted of four 50-minute in-person sessions, one per week.

As reported online September 25 in JAMA Network Open, mixed-effects models demonstrated that light therapy alone was not sufficient to change the timing of sleep. However, compared with sham therapy plus CBT alone, light therapy plus CBT significantly moved sleep onset a mean of 50.1 minutes earlier and, as Dr. Zeitzer indicated, increased total sleep time nightly by a mean of 43.3 minutes.

Light therapy plus CBT also resulted in a seven-fold greater increase in bedtime compliance compared to those receiving sham plus CBT, as well as a mean 0.55-point increase (on a seven-point scale) in subjective evening sleepiness compared with a mean 0.48-point increase for those receiving sham plus CBT.

Dr. Zeitzer said, "The biggest limitation for clinicians at this point is getting a device that can deliver the flashes. We used a bridge beacon and are working with a company (Lumos) to make masks that can deliver the lights."

Dr. Alex Dimitriu, a psychiatrist and sleep medicine specialist in Menlo Park, California, commented by email, "For phase 1, CBT was done over the phone, while in phase 2, CBT was done in person, in the lab; it would be interesting to see what is the 'minimum' amount of CBT, via phone or in-person, that would still be effective."

"It would also be interesting to dive into the CBT interventions further, and see which components were most powerful when combined with light therapy," he told Reuters Health.

"The goal...would be to replicate this system for home use," he said. "While the light emitter could be designed and could be relatively straight forward, the CBT component may be more challenging. Ideally, the CBT could be done online, to allow more people access to this intervention."


JAMA Netw Open 2019.

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