Apparatus and methods for treating psychiatric disorders, mood disorders and circadian rhythm disorders with a multi-stage light protocol are disclosed. The presently disclosed multi-stage light protocol provides a synergistic treatment including up to 4 types of therapies: bright light therapy, extended sleep deprivation therapy, dawn simulation therapy and short to medium wavelength light therapy. According to some embodiments, the first stage of the protocol includes a first time window of 20 minutes during which, for a majority of the time, the light intensity is between 50 lux and 2000 lux. According to some embodiments, the second stage of the protocol includes a second time window of at least 90 minutes during which, for every 10 minute period within the second time window, for a majority of the time, the light intensity is exceeds 100 lux. According to some embodiments, the third stage of the protocol includes a third time window of 60 minutes during which, for a majority of the time, the light intensity exceeds 2000 lux In some embodiments, the light is provided by apparatus including a plurality of LEDs. Typically, the light includes white light having a broad spectrum. In some embodiments, the light further includes light having a medium wavelength, for example, wavelengths between 520 nm and 535 nm.Linvention concerne un dispositif et un procédé destinés à traiter les troubles psychiatriques, les troubles de lhumeur et les troubles des rythmes circadiens au moyen dun protocole de photothérapie multi-niveau. Le protocole de linvention porte sur un traitement synergique pouvant inclure jusquà quatre thérapies: thérapie par forte lumière, thérapie par privation prolongée de sommeil, thérapie avec simulation de laube et photothérapie avec ondes lumineuses courtes à moyennes. Dans certains modes de réalisation, le premier niveau comprend une fenêtre de temps de 20 minutes au cours de laquelle règne la plupart du temps une intensité lumineuse comprise entre 50
