Circadian rhythms and insomnia

Circadian rhythms strongly influence when we are sleepy and when we are alert. If the timing of these rhythms is later than normal, it can contribute to sleep onset insomnia. If the timing is earlier than normal, it can lead to early morning awakening insomnia. Therefore, management of these types of insomnia need to include treatments, such as bright light and melatonin, that will re-time the circadian rhythms to be more in synchrony with the desired timing of sleep. Sleep onset insomnia would benefit from morning light therapy and early evening melatonin administration, while early morning awakening insomnia benefits from late evening bright light therapy and possibly early morning melatonin administration. Chronic insomnia from any original cause will most likely have a behavioral or learned component that should be addressed with cognitive/behavioral therapy. Thus, insomnia usually has multifactorial causes needing a multipronged therapeutic approach.