Light therapy

However, despite its enormous importance to human physiology, no pharmacological compounds targeting the components of the circadian clock system have been identified to date. There are, nevertheless, two therapeutic approaches that are currently used for treatment of circadian-related disorders - full-spectrum and bright light therapy and melatonin therapy. Melatonin is a hormone that is produced by the pineal gland in... 

Light therapy is an alternative treatment for depression associated with seasonal (e.g., winter) exacerbations. Possible side effects include eye strain, headache, insomnia, and hypo-mania.16,17 Also, potentially vulnerable patients, such as those with photosensitivity or a history of skin cancer, should be evaluated carefully prior to therapy.16... 

Changes in the sleep-wake cycle or light-dark cycle can precipitate episodes of mania or depression. Bright light therapy can be used for the treatment of winter depression and can precipitate hypomania, mania, or mixed episodes. 

Bright light therapy (i.e., the patient looking into a 10,000-lux intensity light box for about 30 min/day) may be used for patients with seasonal affective disorder and as adjunctive use for major depression. 

Stege, H. et al., Enzyme plus light therapy to repair DNA damage in ultraviolet-B-irradiated human skin, Proc. Natl. Acad. Sci. USA 97, 1790-1795, 2000. 

Acitretin is most useful for the treatment of severe psoriasis, particularly the pustular and erythrodermic variants. Psoriatic nail changes and arthritis also may respond. Combining the drug with ultraviolet light therapy (Re-UVB, in the case of ultraviolet B radiation, or Re-PUVA, with psoralen plus ultraviolet A radiation) permits the use of lower doses of both acitretin and ultraviolet radiation. Other conditions for which the drug may be especially useful include congenital and acquired hyperkeratotic disorders, such as the ichthyoses and palmoplantar keratodermas, and severe lichen planus. 

Sleep deprivation had no overall beneficial effect on OC symptoms or mood in 16 patients with OCD [Joffe and Swinson 1988). Likewise, in one report, bright light therapy was ineffective in reducing severity of OC symptoms in a small group of patients with OCD [Yoney et al. 1991). 

Rosenthal NE, Sack DA, Gillin JC, et al. Seasonal affective disorder a description of the syndrome and preliminary findings with light therapy. Arch Gen Psychiatry 1984 41 72-80. 

Beedle D, Krasuski J, Janicak PG. Advances in somatic therapies electroconvulsive therapy, repetitive transcranial magnetic stimulation, and bright light therapy. In Janicak PG, Davis JM, Preskorn SH, et al., eds. Principies and practice of psychopharmacotherapy update. 2nd ed. Vol 2. Baltimore Williams Wilkins, 1998. 

Three major hypotheses have been advanced to explain the effects of light therapy ... 

The melatonin hypothesis postulates that winter depression is triggered by alterations in nocturnal melatonin secretion, which acts as a chemical signal of darkness. Thus, by giving light therapy before dawn or after dusk, the light period can be prolonged and secretion of melatonin can be diminished. Evidence that atenolol, which suppresses melatonin secretion, was not an effective therapy for SAD weakens this particular hypothesis ( 148). 

The circadian rhythm amplitude hypothesis postulates that FOSAD is caused by a reduction in the amplitude of various rhythms, which are increased by light therapy. There is evidence that amplitudes of certain rhythms are abnormally low in depression, particularly in FOSAD. This hypothesis has yet to be tested under experimental conditions. 

Also of interest is the report by Anderson and colleagues (154) that found a reduction in the urinary output of norepinephrine and its metabolites in nine female SAD patients treated with light therapy. They concluded that the results were compatible with changes seen after antidepressant drug therapy and recommended controlled trials to confirm this preliminary finding. 

In addition, certain clinical symptoms may be more predictive of response to light therapy. For example, Terman et al. ( 161) found that depressed responders were characterized by more atypical symptoms such as... 

Overall, the ratio of atypical to classic symptoms of depression, rather than severity per se, was the best predictor of a positive response to bright light therapy. 

Some of the most common complaints in patients exposed to bright light therapy include the following ... 

Thus, sleep deprivation may be an alternative somatic approach that holds promise for the treatment of certain depressive disorders, as well as being an aid in elucidating the biological basis of mood disorders (183). Further preliminary evidence indicates a role for sleep deprivation when used concomitantly or consecutively with antidepressants or with bright light therapy (184). 

Parry BL. Light therapy of premenstrual depression. In Lam RW, ed. Seasonal affective disorder and beyond light treatment for SAD and non-SAD conditions, 1st ed. Washington, DC American Psychiatric Press, 1998 173-191. 

Meesters Y, Jansen JHC, Bursma DGM, et al. Light therapy for seasonal affective disorder the effects of timing. Br J Psychiatry 1995 166 607-612. 

Leibeniuft E, Turner E, Feidman-Naim S, et ai. Light therapy in patients with rapid cyciing bipoiar disorder preiiminary resuits. Psychopharmacoi Bull 1995 31 705-710. 

Another recognized type of depression is seasonal affective disorder (SAD). People in far northern or southern latitudes develop this condition in the winter, apparently from lack of sunshine needed to lower the melatonin level in the morning (see Section 13). Light therapy is beneficial.1110 Persons with the SAD syndrome also tend to crave carbohydrates and to stay in bed for 9-10 hours. 

E. The symptoms are not due to the direct physiological effects of a substance (e.g., a drug of abuse, a medication, or other treatment) or a general medical condition (e.g., hyperthyroidism). Note Manic-like episodes that are clearly caused by somatic antidepressant treatment (e.g., medication, electroconvulsive therapy, light therapy) should not count toward a diagnosis of bipolar I disorder. 

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