Course of treatment received by depressed patients

Using data from an observational study of affective disorders, we describe the rates of transition among levels of antidepressant treatment for subjec ts with Major Depressive Disorder (MDD), and relate these changes to change s in clinical status. We report on the treatment received during the first 10 years of follow-up in the Collaborative Depression Study by 555 patients with a diagnosis of MDD of at least one month's duration. This work extend s the initial examination of treatment received during the first eight week s after entry into this study that showed depressed patients to be on low l evels of treatment. Multiplicative intensity models which generalize surviv al analysis models were used to analyse these data. Description of the cour se of treatment of these depressed patients shows that low levels of treatm ent persist for these patients across subsequent episodes, and that these e pisodes, like the index one, are characterized by extended time in a sympto matic subcriterion state after acute symptoms have improved. These longterm descriptions of treatment support the initial hypothesis that these CDS pa tients were undertreated. The long-term tendency toward undertreatment seem s to persist even as newer treatments become available and widely accepted in practice. (C) 1999 Elsevier Science Ltd. All rights reserved.