Ketamine's Actions on Rumination Mechanisms as an Antidepressant
Status:
Completed
Trial end date:
2018-05-01
Target enrollment:
Participant gender:
Summary
Rumination and anhedonia are two of the most common characteristics of depression that
persist during remission and are not easily targeted by commonly prescribed antidepressants.
Ketamine, an NMDA receptor antagonist, has emerged within the last decade as a potent,
fast-acting antidepressant that can significantly improve anhedonia as early as two hours
after a single infusion. The brain mechanisms, however, by which ketamine exerts its
antidepressant action remain largely unknown. The aim of this study is to examine the early
antidepressant action of ketamine, 2h post infusion, in patients who remitted from depression
using fMRI. Participants are scanned while performing a personalised, autobiographical,
emotional memory task and a monetary reward task. Ketamine is expected to reduce the
activation of limbic areas such as the amygdala during emotional memory recall. Increased
activations after ketamine are expected in reward processing areas, including striatal
regions.