In order to determine the usage pattern of light therapy (LT), we performed a survey of all psychiatric hospitals in Germany in 1992. Our data reveal that 13% of all psychiatric hospitals perform LT and another 7% indicate their interest in this treatment. Stratification into different treatment facilities demonstrates that 57% of the psychiatric university hospitals use LT. The usage of LT started in Germany in 1982 and there was a sharp rise from 1987 onwards. The majority of hospitals (89% of those hospitals which use LT) use LT successfully for the treatment of seasonal affective disorder (SAD) and its subsyndromal form followed by non-SAD depression (68%). LT is used as monotherapy in 71% of SAD patients compared with 34% in non-SAD depression.