Disturbed sleep is an intrinsic symptom of depression and may precede or even initiate it. Thus, it is surprising that depriving a patient of sleep can induce improvement, often within hours - however usually with relapse following recovery sleep. Clinical trials of early and late partial sleep deprivation, or shifting sleep earlier, suggest a critical circadian phase where wakefulness is necessary for the antidepressant response. Combination with medication or light therapy can maintain improvement. There is now sufficient evidence for many chronotherapeutic combinations (Table) to support the use of “wake therapy” - the fastest antidepressant modality known - in general psychiatric practice (1).

[Circadian and Sleep Therapies of Major Depression]