STRUCTURAL VALIDITY OF MADRS DURING ANTIDEPRESSANT TREATMENT

In order to assess the internal structure of MADRS, a principal compon ent analysis was performed in a group of 137 patients suffering from D SM-III major depression (MADRS score at baseline > 20) receiving a 4 w eek treatment in three double-blind drug trials (medifoxamine vs clomi pramine, imipramine or amineptine). Prior to antidepressant treatment, three factors could be identified with 32%, 12% and 11.5% of explaine d variance. The first factor corresponded to the global severity of de pression whereas the second, with sleep and appetite items scoring hig h, could be postulated as a somatic factor, After 28 days of antidepre ssant treatment (mean MADRS total score = 13.3), only one factor could be substantiated, representing 66% of total variance. The study was p rimarily based on data obtained without rotation, which ensures the in dependence of the different factors, The good internal consistency of MADRS accounts for the high correlation of all items with the first fa ctor (r = 0.95), MARS appears as a unidimensional scale more oriented towards psychic as opposed to somatic aspects of depression.