[Methodological problems of depression research]

Controlled clinical trials on the effect of the new antidepressive drugs are encumbered by a number of methodological weaknesses, one of which is lack of placebo control in many studies. The main problem in research into depression is, however, the overlooked issue of how to validate the diagnosis of depression. The agreed diagnostic inclusion criteria in these studies are the diagnostic criteria from the DSM-III or the ICD-10. These disease classifications are in accordance with what has been called the epidemiological disease model. The conclusions of all clinical trials are, however, based on the assumption of a different disease model, the bio-medical disease model. There has truly been a documented effect of these drugs in controlled clinical trials of groups of patients diagnosed with depression, but this conclusion is not stronger than the validity of the diagnosis of depression itself. The categorization of antidepressive drugs as drugs with antidepressive effect has a similar basis even if these drugs were introduced on the basis of a theory of the neurobiology of depression. It is therefore perhaps unclear what has really been documented in these studies. The time has come for a closer inspection of how to use the controlled clinical trial in the field of depression, as well as for a discussion and clarification of what we mean when we use the diagnosis of depression.