Light therapy is used to ease mood disorders such as seasonal affective disorder, or SAD; depression; or insomnia, explains Mayo Clinic. Light therapy is also used to enhance the effect of antidepressants or psychotherapy.
Other people use light therapy for jet lag, insomnia, dementia and to adjust to a midnight shift at work, states Mayo Clinic. Therapeutic uses of light include treating skin disorders such as psoriasis, according to WebMD. Even exposure to sunlight eases the condition in some people. In other cases, a person is given a dose of psoralen and then exposed to ultraviolet light. Some people are exposed to UV light after an application of coal tar on their lesions.