Evening light can disrupt mood in bipolar disorder. In short, blue spectrum light emitted by many digital devices suppresses melatonin, worsening two systems that are already fragile in people with mood disorders: sleep and circadian rhythms.1 There are simple solutions to correct this problem, and they may also help the 40% of Americans who’ve made screentime a part of their bedtime.2
Blue light blockers
The first step is to wear amber tinted glasses that block blue spectrum light in the evening. This approach was studied in a small randomized controlled-trial of inpatients with mania.1 Manic symptoms improved over 7 days with the blue-light blockers, and the effect size was large. The protocol for this Dark Therapy required patients to either wear the glasses or remain in a pitch-black dark room from 6:00 pm to 8:00 am. After they recovered, they were able to ease the routine to a later start time. Blue light blockers appear to have preventative benefits as well, and, it’s reasonable to wear them 1 to 2 hours before bedtime when symptoms are mild or prevention is the goal.
Which glasses work?
To work well, the glasses should block at least 90% of blue light, and most products don’t have that rigor. The Dark Therapy trial used glasses from lowbluelights.com (any pair will work from that site). Other studies have used the less expensive Uvex models, which also earned high marks in a Consumer Reports test. For under $10, there’s the Uvex Ultraspec 2000 model S0360X, which fits over regular glasses, and the Uvex Skyper model S1933X.
Blue blocking glasses are uncomfortable to sleep in, so a pitch-dark bedroom was part of the overnight pro
tocol in the Dark Therapy trial. Eliminating bedroom light may help depression as well as mania. Bedroom light as low as 5 lux (ie, a nightlight) has been linked to higher rates of depression, so pitch dark is the goal here.3 Ideas for darkening the bedroom include black-out curtains, eye masks, electrical tape over LEDs, towels or draft snakes under doors, or sleeping in the basement.
Sleeping with the TV on
What if patients find it difficult to sleep without the TV? Familiar voices are comforting, and patients often use TV to drown out the ruminative thoughts that would otherwise keep them up all night. Some TV sets allow the monitor to turn off, but for others the only solution is to shift to podcasts, radio, or music. Weightless, an ambient track by Marconi Union, was developed in conjunction with sleep researchers. In a small study, it produced greater relaxation and sleep than comparably mellow tunes.
Dr Aiken does not accept honoraria from pharmaceutical companies but receives honoraria from W.W. Norton & Co. for Bipolar, Not So Much, which he coauthored with James Phelps, MD.
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