Dear Dr. Aiken: I enjoyed Dr. Phelps’ discussion of blue-light blockers as a treatment for mania in the February issue. I’m wondering: Could these work for jet lag?

Dr. Aiken: Jet lag happens when people fly across multiple time zones. The body’s internal clock gets out of sync with the outside signals of sunrise and sunset. The result is insomnia, poor concentration, fatigue, and gastrointestinal symptoms. The problem doesn’t happen on a road trip because the body has time to adjust to the new time zone. The way to prevent jet lag is replicate those gradual changes in sleep and sunlight in the 3–7 days before flying, ie, to live as if travelling by car in those preflight days.

For eastbound travel, that means going to bed—and entering darkness—an hour earlier each night before the flight. That’s where the blue-light blockers come in handy. By eliminating blue light, these glasses cause the brain to think it’s in pitch darkness (eg, Uvex S0360X Ultra-spec 2000 or www.lowbluelights.com). Alternatively, people can take melatonin a few hours before bed while shifting their sleep schedule. That also eases jet lag, but blue-light blockers, which raise endogenous melatonin, can work as well.

A custom preflight schedule can be generated at www.jetlagrooster.com. On that site, click the option to “take melatonin” and the schedule will include an ideal time to take melatonin (0.5–3 mg). That’s also when the blue-light blockers should be put on. Wear them until entering a dark bedroom for sleep, and then use a timed light to wake up earlier, closer to the time of sunrise at your eastern destination (Eastman CI & Burgess HJ, Sleep Med Clin 2009;4(2):241–255). The site also has strategies for westward travel. In that case, sleep needs to gradually shift later in the days before flight, and evening light—rather than evening darkness—is used.

Though often thought of as a potent destabilizer in bipolar disorder, jet lag is equally problematic in schizophrenia and depression. Westward travel is more likely to cause depression, while mania and psychosis are triggered by travel east (mnemonic: west rhymes with depressed). The risk is significant when flying over 3 or more time zones; travel across 1–2 is usually not problematic (Inder ML et al, Aust N Z J Psych 2016;50(3):220–227).