"The early bird catches the worm"-Prediction of early response and its importance for treatment outcome in a naturalistic setting of cognitive behaviour therapy.

Objective: Knowledge about predictors of early response (ER) remains limited. This study examined patient, process, and therapist variables to predict ER in a naturalistic setting.

Research Design And Methods: Data from 493 psychotherapy outpatients were analysed. ER was defined by a ≥25% reduction in general psychological distress (ER percent) and by the reliable change index (ER RCI) within the first 10 sessions measured by the Brief Symptom Inventory-18. ER prediction was determined using logistic regression. General psychological distress (GSI) throughout treatment in patients with and without ER was modelled using a multilevel linear model. This model aimed to predict GSI over treatment using repeated measurements, considering group affiliation (ER percent vs. no ER percent), controlled for other predictors.

Results: The prevalence of ER percent and ER RCI were 63.6% and 47.5%, respectively. GSI and therapeutic relationship significantly predicted ER (ER percent: χ (6) 70.32, p < .001, Nagelkerkes R  = .19; ER RCI: χ (6) 134.71, p < .001, Nagelkerkes R  = .35). Patients who rated the therapeutic relationship more positively were more likely to achieve ER (OR = 1.10). Difference in outcomes between patients with and without ER during treatment was influenced by factors such as therapeutic relationship, GSI, therapist experience, and mental comorbidities. Including these variables improved the predictive model from AIC = 17,042.98 to AIC = 16,730.24.

Conclusion: The therapeutic relationship is a crucial predictor of ER. Patients achieving ER tend to have better outcome than those without ER. The early phase of therapy warrants particular attention to enhance psychotherapy outcomes.