Is the Ultimate Treatment Response Predictable with Early Response in Major Depressive Episode?

New evidence suggests that the efficacy of antidepressants occurs within the first weeks of treatment and this early response predicts the later response. The purpose of the present study was to investigate if the partial response in the first week predicts the response at the end of treatment in patients with major depressive disorder who are treated with either antidepressant medication or electroconvulsive therapy.

Inpatients from Dokuz Eylül University Hospital with a major depressive episode, treated with antidepressant medication (n=52) or electroconvulsive therapy (ECT) (n=48), were recruited for the study. The data were retrospectively collected to decide whether a 25% decrease in the Hamilton Depression Rating Scale (HDRS) score at the first week of treatment predicts a 50% decrease at the third week using validity analysis. In addition, the effects of socio-demographic and clinical variables on the treatment response were assessed.

A 25% decrease in the HDRS score in the first week of treatment predicted a 50% decrease in the HDRS score in the third week with a 78.3% positive predictive value, 62.1% negative predictive value, 62.1% sensitivity, and 78.3% specificity for antidepressant medications and an 88% positive predictive value, 52.2% negative predictive value, 66.7% sensitivity, and 80% specificity for ECT. The number of previous hospitalizations, comorbid medical illnesses, number of depressive episodes, duration of illness, and duration of the current episode were related to the treatment response.

Treatment response in the first week predicted the response in the third week with a high specificity and a high positive predictive value. Close monitoring of the response from the first week of treatment may thus help the clinician to predict the subsequent response.