Rapid and slow responders to eating disorder treatment: a comparison on clinically relevant variables.

OBJECTIVE: Speed of response to eating disorder treatment is a reliable predictor of relapse, with rapid response predicting improved outcomes. This study investigated whether rapid, slow, and nonresponders could be differentiated on clinically relevant variables, and possibly identified prior to treatment. METHOD: Female patients (N = 181) were classified as rapid, slow, or nonresponders based on the speed and magnitude with which they interrupted their bingeing and/or vomiting symptoms, and were compared on eating disorder behaviors and psychopathology and general psychopathology. RESULTS: The rapid response group was marginally older and had a slightly shorter course of treatment than the slow response group. The rapid response group also had significantly fewer pretreatment binge episodes, and a longer course of treatment than the nonresponse group. However, the three response groups were not significantly different on any other examined variables. DISCUSSION: The only pretreatment variable that differentiated response groups was symptom frequency, in that rapid responders had fewer binge episodes than nonresponders. No pre-existing variables differentiated rapid and slow response. Given that few individual pre-existing differences that might account for speed of response were identified, the clinical importance of facilitating a rapid response to treatment for all patients is discussed.