Treatment indications for light therapy.

Light therapy (LT) has become increasingly popular in various countries around the world in the last decade. For instance, according to a recent survey carried out in Germany in 1992, 13% (n = 56) of all German psychiatric hospitals (n = 422) used LT for different treatment indications and another 8% indicated their interest to do so. Among university facilities LT is even more popular, with a percentage of 57%. Although the most frequently used treatment indication for LT is seasonal affective disorder (SAD) or its subsyndromal form (S-SAD) it is apparent that other forms of depression e.g. non-seasonal forms, either acute or chronic are also a target for this new treatment modality. There is a number of studies supporting the use of LT for SAD (for review), however there are just a few studies for non-seasonal depression or for the other treatment indications (for review).