Circadian Rhythm Sleep Disorders are a distinct class of sleep disorders characterized by a mismatch between the desired timing of sleep and the ability to fall and remain asleep. If remain untreated, these sleep problems can lead to insomnia and excessive daytime sleepiness, with severe undesirable health, psychological, and social consequences1, not only disturbing daily functioning but also leading to tragic outcomes.
Treatments for Circadian Rhythm Sleep Disorders (CRSD) There are several treatment options designed to address the desynchronization, including chronotherapy (schedule-based treatment), phototherapy (light-based treatment) and melatonin administration. Furthermore, other treatments such as traditional hypnotics, cognitive behavioral therapy (CBT) or treatments for excessive daytime sleepiness such as stimulants can also be used in CRSD.
Behavioural therapy Depending on the disorder, certain behavioural therapies such as maintaining regular sleep-wake times, avoiding naps, getting regular exercise, avoiding nicotine, caffeine, and stimulating activities within several hours before desired bedtime, may help alleviate the symptoms, but their effectiveness has not been proven over time. In addition, it is known that light exposure could also affect those who suffer from circadian rhythm disorder: people with delayed sleep phase syndrome should minimize their exposure to light during evening and night time by reducing indoor illumination (avoiding bright TV, cellular and computer screens). Those with advanced sleep phase disorder, who fall asleep early in the evening and wake up very early in the morning, should increase light exposure in the evenings by keeping the lights on at home or spending time outdoors.
Bright light therapy Bright light therapy for Circadian Rhythm Sleep Disorders is an effective treatment option. Timed exposure to bright light (natural, artificial or a combination) can shift the sleep-wake cycle to earlier or later times, in order to correct the misalignment between the circadian system and the desired sleep-wake schedule. Several studies have established that the human circadian system is very sensitive to light, and that the efficacy of light in resetting circadian rhythms is determined by the dose, light wave, and time-of-day that the light is administered2 3.
Medication Medications usually either promote sleep, as done by hypnotic medications, or promote daytime wakefulness, as done by stimulants. External (exogenous) melatonin treatment has been shown to have both sleep-inducing and biological clock readjustment effects. It can induce drowsiness or sleep, especially when administered during the biological daytime when the body’s self-produced melatonin is not present, and can also adjust the timing of the central biological clock.
Timed melatonin administration Melatonin products were found to be effective in treating Circadian Rhythm Sleep Disorders. Melatonin administration in the evening has been shown to benefit patients with Delayed Sleep Phase Disorder (who only fall asleep late at night) by advancing circadian rhythms and sleep timing4. Melatonin has also been successful in treating biological clock misalignments (free-running) in blind patients5, shift work and jet lag6.
