Prognostic and prescriptive predictors of improvement in a naturalistic study on inpatient and day hospital treatment of depression

Background: The study aimed to identify prognostic (associated with general outcome) and prescriptive (associated with differential outcome in two different settings) predictors of improvement in a naturalistic multi-center study on inpatient and day hospital treatment in major depressive disorder (MDD). Methods: 250 inpatients and 250 day hospital patients of eight psychosomatic hospitals were assessed at admission, discharge and a 3-months follow-up. Primary outcome was defined as a reduction of depressive symptomatology from admission to discharge and from discharge to follow-up (QIDS-C, total score). Percent improvement scores at discharge and at follow-up were entered as dependent variables into two General Linear Models with a set of predictor variables and the respective interaction terms with treatment setting. The selection of predictor sets was guided by statistical methods of variable preselection (LASSO). Results: Three variables were associated with less improvement from admission to discharge: the number of additional axis-I diagnoses, axis-II co-morbidity (SCID) and lower motivation (expert assessment). Social support (F-SozU) predicted symptom course between discharge and 3-month followup. Patients with no absent / sick days prior to admission showed a less favorable symptom course after discharge when treated as inpatients. Conclusions: Patients with co-morbidity show less improvement during the active treatment phase. Motivation can be considered a prerequisite for symptom reduction, whereas social support seems to be an important factor for the maintenance of treatment gains. The lack in prescriptive predictors found may point to the fact that inpatient and day hospital treatment have comparable effects for most subgroups of patients with MDD. (C) 2016 Elsevier B.V. All rights reserved.