Background Ketamine is a rapid-acting antidepressant that produces acute dissociative symptoms. In routine care, the respective contributions of therapeutic expectations and dissociative symptoms to antidepressant response, and the directionality of their associations with depressive symptom change, remain poorly characterized.
Key Points Question What are the effects of ketamine on belief updating in patients with treatment-resistant depression (TRD)? Findings This case-control study in patients with TRD showed that belief updating became more optimistically biased as soon as 4 hours after a first ketamine infusion. This early cognitive effect of ketamine was formalized by stronger asymmetrical reinforcement learning...
Treatment resistant depression (TRD) is a tremendous health problem that has encouraged novel treatment strategies involving sub-anesthetic ketamine infusions. While ketamine induces rapid and sustained clinical improvement, its cognitive effects are less well known. Here we tested if ketamine alters the negative expectancies about the future that are insensitive to disconfirming information,...
Background: Facial emotion recognition deficits are well defined in depression but understudied in treatment-resistant depression (TRD). Over the past decades, subanesthetic doses of ketamine have emerged as an effective treatment for TRD, but its effect on affective processing is still little known. Approaches from computational psychiatry, such as sequential evidence sampling models of...