Salem Press

Magill's Medical Guide covers diseases, disorders, treatments, procedures, specialties, anatomy, biology, and issues in an A-Z format, with sidebars addressing recent developments in medicine and concise information boxes for all diseases and disorders. Below is an excerpt from the Guide's essay on light therapy.

Light Therapy
Light Therapy, or phototherapy, treats a variety of disorders. By exposing individuals to different kinds of light (for example, monochromatic, polychromatic, ultraviolet), symptoms can often be delayed, reduced, and eradicated. Immunological and neuroendocrine systems are thought to play key roles in response to this type of treatment.

Best known in psychiatry, light therapy has been used to treat seasonal affective disorder (SAD), or winter depression; bulimia nervosa; sleep disorders; and "sundowner's syndrome:, the late afternoon confusion and agitation sometimes accompanying Alzheimer's disease. Reduced environmental light is thought to be a factor in the etiology, onset, or maintenance of these disorders. Thus, treatment involves exposing individuals to bright, full-spectrum light for fixed periods to time. Duration of exposure and light intensity vary by the disorder and individual treated.

In dermatology and oncology, light therapy has been used to treat psoriasis, skin ulcers, tumors, and esophageal cancers. The type of light and the intensities used, however, vary considerably from those applied for the treatment of psychiatric disorders.

SEASONAL AFFECTIVE DISORDER
Causes: Unknown; probably hormone and neurotransmitter dysfunction

Symptoms: Seasonal pattern of depression, which may include anxiety, loss of interest in sex, abnormal menstruation, suicidal thoughts, withdrawal, reduced energy

Duration: Chronic during winter months

Treatments: Phototherapy, serotoninergic antidepressants