Electroencephalography and Magnetoencephalography Signatures of Ketamine Treatment in Depression: A Literature Review

Introduction: Ketamine has been shown to have rapid antidepressant effects. In addition, the use of EEG in depression offers a new approach to diagnose patients. It is necessary to understand locational-based EEG and MEG changes following ketamine in patients with depression to establish a potential biomarker panel. This study sought to identify consistent changes in band power as well as to highlight brain regions of interest.

Methods: This review examines studies published in the last 25 years that have trialed ketamine treatment in patients with depression and that utilize EEG or MEG. The studies report on spectral power changes in different bands as well as asymmetry, theta cordance, complexity, event-related potentials, and sleep studies.

Discussion: Resting state was the most reported. An EEG profile was identified of decreased theta, alpha, low beta and increased high beta and gamma following ketamine treatment, primarily in frontal regions. Although the antidepressant effects of ketamine are clear, the EEG research available on ketamine treatment in patients with depression is not comprehensive. Further research in more diverse age groups and larger studies is necessary as well as on the underlying ketamine mechanisms of affecting power bands.

Conclusion: Overall, a largely consistent EEG profile of decreased theta, alpha, low beta and increased high beta and gamma following ketamine treatment was identified primarily in frontal regions. Thus, EEG may be a useful tool for mechanistic treatment monitoring in depression patients subject to ketamine therapy.