SAN DIEGO – Melatonin supplements may be popular to shift circadian rhythms, but bright-light therapy is more effective, Milton Erman, M.D., said at a psychopharmacology congress sponsored by the Neuroscience Education Institute.
People with sleep disorders from working night shifts especially may benefit from therapy to shift their circadian rhythms to match the imposed sleep schedule, said Dr. Erman of the University of California, San Diego.
If the patient mainly is bothered by disrupted or insufficient sleep (wakefulness) or by excessive sleepiness while awake, try focusing treatment on one or the other, he suggested. If sleep problems include both wakefulness and sleepiness, it may be best to try to shift the patient's circadian rhythm.
Light therapy is inexpensive and safe for shifting circadian rhythm. Bright light or light plus exercise worked better than exercise alone, melatonin alone, or placebo to treat night-shift workers in a 1999 study.
Light therapy or light plus exercise shifted sleep/wake phases by 7–8 hours, compared with approximately 5 hours for melatonin and 3 hours with placebo. Patients achieved close to 7.5 hours of sleep per sleep phase with light therapy or light plus exercise, compared with approximately 6.5 hours of sleep with melatonin or placebo, Dr. Erman said.
To shift the circadian sleep phase, the timing of therapy is critical, whether using light, exercise, or melatonin. Any of these in the morning will advance the circadian rhythm so the patient goes to sleep earlier. To stay up later than usual, delay sleep by exercising or using light or melatonin in the late afternoon or early evening, he said.
For patients complaining mainly of wakefulness, benzodiazepines or nonbenzodiazepine hypnotics such as zolpidem (Ambien) can improve the quantity and quality of sleep, but studies suggest that improvements in job performance are short term. For sleepiness, modafinil (Provigil) is safer than stimulants and is approved to treat chronic shift-work disorder.
Dr. Erman has been a speaker and consultant for, or received honoraria from, the companies that make zolpidem and modafinil.