Bright light therapy (BLT) is a type of chronotherapy used to treat various psychiatric conditions, including seasonal affective disorder, sun-downing in Alzheimer’s dementia, bulimia, postpartum depression, non-seasonal depression, and various others. Not to be confused with phototherapy, BLT uses ultraviolet FILTERED light. Phototherapy, used to treat skin diseases such as eczema, on the other hand, uses ultraviolet UNFILTERED light.
BLT therapy is administered using a light box, which can be purchased from a variety of companies, and even through Amazon. The most effective light intensity is 10,000 lux. BLT should be administered before dawn around 0700 hours for 30 minutes. The individual should sit within 2 feet of the light box, although this varies by manufacturer. Also, there has been some research using BLT in the early afternoon for an energy booster. Keep in mind, BLT works through the eyes, therefore the individual must keep his or her eyes open while not staring directly at the light.
Response to BLT generally occurs in 1 to 2 days and remission within 2 to 4 weeks. Side effects include headache, nausea, and eye strain. These can be mitigated by sitting farther from box. Adverse effects include hypomania. Be careful when administering BLT to individuals on photosensitizing medications or those with suspected underlying bipolar disorder.
Things to Remember:
Feel free to check out my BLT PowerPoint presentation under the Projects tab.
I also attached a meta-analysis of evidence regarding the use of BLT published in 2005.