Early distress score instability predicts outcome in brief psychotherapy.

Among psychotherapy patients, unstable early distress scores are known to predict substantial intersession improvement later in treatment. The evidence has been ambiguous as to whether early distress instability also predicts outcome. We investigated the links among early distress instability, later intersession improvement, and outcome. In a sample of 1,796 students treated with brief psychotherapy at university counseling centers, we sought to predict intersession improvement and treatment outcome from an index of distress instability, as assessed during the first four treatment sessions. Large intersession shifts late in treatment appeared to mediate the link between early distress instability and outcome. These relationships were limited to participants who demonstrated early score shifts larger than measurement error. As hypothesized by dynamic systems theory, some psychotherapy patients experience stepwise improvement that is preceded by early instability in distress scores. However, the effect size linking early instability to outcome is small. Sudden gains may not be the optimal measure to elucidate these relationships. (PsycInfo Database Record (c) 2023 APA, all rights reserved).