Single-Item Anhedonia in Schizophrenia Marks Illness Severity but Does Not Independently Predict Outcomes: An Item-Level Reanalysis of the Clinical Antipsychotic Trials of Intervention Effectiveness Trial

Introduction

Anhedonia has been proposed as a marker of poor functional outcomes in schizophrenia. A model that omits baseline functioning estimates a different quantity from one that includes it: the former assesses whether anhedonia identifies patients who function worse later, and the later assesses whether it adds prognostic information beyond baseline functioning. We estimated both associations using data from the Clinical Antipsychotic Trials of Intervention Effectiveness trial.