Obesity is rarely a harbinger of recovery with antidepressant therapy, but at least 3 treatments may be exceptions to that rule. A review of Freeman MP, Hock RS, Papakostas GI, et al. Body Mass Index as a Moderator of Treatment Response to Ketamine for Major Depressive Disorder. J Clin Psychopharmacol. 2020;40(3):287‐292. [Link]

Published On: 5/20/20

Duration: 2 minutes, 52 seconds

Transcript: 

Obesity generally predicts a worse response with most antidepressant therapies, but there are exceptions. In the past year we’ve reported on studies showing better responses in obesity to bupropion – Wellbutrin – and methylfolate.  This study adds ketamine to that list.

It’s a post-hoc analysis of a 99 person randomized controlled trial, and they found that ketamine’s antidepressant effects rose steadily with the patient’s BMI. Gender, on the ohther hand, did not influence response. In the study, ketamine was dosed based on weight.

The results build on 2 earlier papers that arrived at the same conclusion.

We don’t know why ketamine works better in obese patients. An intriguing possibility is that obesity is a sign of inflammation. In the case of bupropion and methylfoate, the preferential resonpse in obesity has been linked to inflammation. Ketamine dos have anti-inflammatory properties, but we need more studies to confirm this lead. Adipokine dysregulation and differences in metabolism of ketamine in obese individuals may also explain the results.

The study, lead by Marlene Freeman and Maurizio Fauva at Mass General, appeared in the journal of clinical psychopharmacology and was sponsored by the NIMH.

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