Application of light therapy in psychiatry

Summary Bright light therapy for more than two decades is used in psychiatry. A lot of data about mechanism of action, therapeutic effect and side effects of light therapy were collected, methodology of application of light therapies was created. It is known that light therapy regulates circadian phases acting on retina of eye. The best results of light therapy were obtained using wide spectrum bright light, but not the red light. Although there is some data show importance of  short wave length visible spectrum light, it is still some doubts about ocular safety of short wavelength lamps. Modern methodologies of application of light therapy recommends   10000 lux  30 minutes sessions every morning, but it is possible that for particular patient optimal light therapy timing may be individual. Light therapy may be used in outpatient and inpatient settings. It is important to ensure patients compliance with treatment, because compliance problems are usual not only for medication but for light therapy too. Most of side effects of light therapy is mild and transient. Sometimes there is a possibility of hypomania. Relative contraindications of light therapy is eye diseases, systemic diseases that affects retina, usage of photosensitizing medications. In such cases consultation of ophthalmologist should be performed. Light therapy is used for several mental disorders. The most evidence is provided about effect of light therapy on winter depression of seasonal affective disorder. American Psychiatric Association recommends this method for outpatient treatment of seasonal depression. Light therapy is also efective for the treatment of subsyndromal seasonal affective disorder. Evidence shows the effect of light therapy in case of nonseasonal depression and it can be used as adjunctive to antidepressant treatment and sometimes as mono-therapy. There is some data about possible application of light therapy in the treatment of other mental disorders. Light therapy is safe and increasingly used method of biological therapy in psychiatry. Light therapy can be used in outpatient and inpatient settings, with paying attention to necessity to ensure availability of light therapy equipment and professional supervision of proper treatment regimen.