Correction to: Neuropsychopharmacology https://doi.org/10.1038/s41386-020-0663-6, published online 06 April 2020

Following the publication of this article, the authors have noticed that the definition of response in the legend of Fig. 2 of the original manuscript was incorrect. The corrected text is as follows:

Relationship between (2S,6S;2R,6R)-hydroxynorketamine (HNK) Cmax and antidepressant response to ketamine. The figure plots the difference in MADRS total score between ketamine and placebo arms (response; ketamine minus placebo) by (2S,6S;2R,6R)-HNK Cmax, at each timepoint. The slope for each relationship (with 95% confidence interval) is provided (see also Supplementary Table S2). Increased (2S,6S;2R,6R)-HNK maximum concentration was associated with less clinical response, but this relationship was most robust at later timepoints. MADRS Montgomery-Asberg Depression Rating Scale.

The scientific conclusions of this paper have not been affected.