Early Improvement and Serum Concentrations of Citalopram to Predict Antidepressant Drug Response of Patients with Major Depression

Post hoc analyses of clinical trials have shown that early improvement around day 14 is highly predictive for later response. More- over, evidence has been given that suffi ciently high concentrations of antidepressant drugs in blood are required to attain response. In this study, we determined cut-off levels for citalo- pram serum concentrations and clinical improve- ment during the early phase of treatment to predict later response and the predictive power of these measures either alone or in combination. Methods: Inpatients with depressive disorder according to ICD-10 who received citalopram were included. Psychopathology was assessed by the 17-item Hamilton Depression (HAMD-17) rating s…