Bright Light Therapy (BLT)

Bright Light Therapy is the key treatment method used for Seasonal Affective Disorder (SAD) a form of depression that most commonly occurs in winter and is generally thought to be a result of reduced light levels.  BLT involves the administration of strong light via an artificial light source for specified periods of time.
Very little research into the efficacy of BLT has been carried out in Australia as SAD is more commonly found in countries closer to the north and south poles where sunlight is limited in winter.  Recent research conducted overseas, has shown that BLT may be very useful for treating a range of conditions other than SAD, including uni- and bipolar major depression, ante- and postnatal depression, Bulimia, and ADHD.

What is involved?

For SAD, Bright Light Therapy is traditionally self-administered following the purchase of a light device (many are available online and can be purchased from overseas).  It is advisable that a trained healthcare professional is involved in at least the initial stages of the treatment process due to the varying lengths of time treatment may be needed per individual, and possible side effects of too much light. However, in many cases BLT can be easily self-regulated and highly useful as a self-management approach for people with symptoms of SAD.

Light therapy involves sitting in front of a specially devised light device (normally in the morning) for a period of time. Traditionally this has been for periods of 1-2 hours in front of a 2,500 lux light-box (indoor lighting is normally less than 500 lux), however more recent research has shown that sitting in front of a 10,000 lux light-box for 30 minutes showed similar results with added convenience.  This has now become the clinical standard.
Although there has been increasing use of light therapy for conditions other than SAD overseas, it is not a commonly used treatment method in Australia.
Possible side effects of BLT include:

• eye strain or visual disturbances 
• headache 
• agitation or feeling "wired"
• nausea 
• sweating  
• sedation

These side effects are generally mild and subside with time or by reducing the dose of light. Hypomania and mania have also been reported as uncommon but serious side effects of light therapy. Fluorescent light therapy using 2,500 lux to l0,000 lux is considered relatively safe on the eyes.

References:

Australian National University

Canadian Consensus Guidelines for the Treatment of Seasonal Affective Disorder:
A Summary of the Report of the Canadian Consensus Group on SAD
Editors - Raymond W. Lam and Anthony J. Levitt

Light therapy for seasonal and nonseasonal depression: Efficacy, protocol, safety, and side effects
CNS Spectrums, 10, 647-663
Michael Terman and Jiuan Su-Terman
2005 

Light treatment for nonseasonal depression: speed, efficacy, and combined treatment
Journal of Affective Disorders 49, 109–117
Daniel F. Kripke*
1998

The Efficacy of Light Therapy in the Treatment of Mood Disorders: A Review and Meta-Analysis of the Evidence, The American Journal of Psychiatry