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.

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).

Since Rosenthal et al published their first study about the effects of light treatment on mood in patients suffering from winter depression, many research centres have become interested in the study and treatment of seasonal affective disorders (SAD), one of them being the department of Biological Psychiatry in Groningen. In 1987, we started the first experiments under the inspiring direction of Prof. Rudi van den Hoofdakker and hundreds of patients have participated in various investigations ever since.

The present explosive growth of interest in the therapeutic possibilities of exposure to light was triggered by a patient, Herbert Kern. He suffered from episodic depressive and manic complaints and discovered, by registering these over the years, a seasonal pattern in their occurrence. Discussions with scientists of the NIMH resulted in his participation in a bright light-treatment experiment when he was depressed in the winter of 1980-1981. He recovered.

Next, the same group of investigators defined the criteria for a new syndrome, Seasonal Affective Disorder (SAD): a history of major affective disorder (according to the Research Diagnostic Criteria), at least two consecutive years in which the depressions have occurred during fall or winter and remitted in the following spring or summer, and the absence of any clear-cut seasonally changing psychosocial variable, such as work, stress and so on.

Revue à travers les données de la littérature, la dépression apparaît comme un sujet de recherche très important, qui a déjà suscité de nombreuses théories chronobiologiques, souvent fondées sur des ≪critères diagnostiques objectifs≫. En revanche, l’impact thérapeutique de ces approches reste souvent limité à de rares services ultraspécialisés où les patients déprimés sont adressés en dernier recours.

Dans cet article, les auteurs passent en revue quelques-unes des principales données de la littérature, en particulier celles qui concernent les aspects chronobiologiques de la dépression. Les investigations sophistiquées réalisées dans les unités de recherche peuvent avoir certaines conséquences cliniques et pratiques qui sont également évoquées. En effet, une évaluation clinique soigneuse, orientée sur des bases chronobiologiques suffit bien souvent à proposer des traitements individuels assez simples. Parmi ceux-ci, la privation partielle de sommeil (PPS) représente un moyen utile, permettant une amélioration rapide, mais malheureusement souvent imprévisible et transitoire, des troubles de l’humeur. Il semble possible de rendre plus fiables les PPS grâce à des interventions sur la température, la prise de nourriture et l’exposition à la lumiére.

De plus, les auteurs décrivent un moyen possible de pérenniser les effets antidépresseurs de la PPS par des «microprivations de sommeil» réalisées pendant 15 min, à un moment spécifique de la nuit. Les résultats concernant 11 patients déprimés graves soumis à cette méthode sont exposés, 7 de ces sujets étant maintenus depuis 6 à 20 mois dans un état euthymique.