Phototherapy is comparable to the light received on a clear day a half-hour after sunrise. Optimal phototherapy provides 10,000 lux for up to 30 minutes per day. Older light boxes of 2,500 lux require longer treatments of up to two hours. Phototherapy, which must be prescribed by a psychiatrist, is most successful if started at the onset of symptoms. Treatment is usually conducted in the morning and may be initiated by a device that simulates the day's first light, known as a dawn simulator.
Phototherapy works via the eyes.
Light boxes can be obtained from a number of companies that specialize in phototherapy devices. Some insurance companies cover light boxes but will require a written prescription and may request clear documentation of a seasonal form of depression. Response to light therapy typically occurs in two to four days. Side effects can include agitation, irritability, eyestrain and dry skin. Tricyclic antidepressants, monoamine oxidase inhibitors, Wellbutrin and Lithium have also been used successfully, but generally patients experience more side effects.