Section on the Neurobiology and Treatment of Mood Disorders, National Institute of Mental Health, National Institutes of Health, Bethesda, Maryland, USA.
2 papers in the library · 10 citations · publishing 2024-2025
People who received ketamine for depression in early clinical trials at the National Institute of Mental Health (NIMH) were more likely to obtain ketamine or esketamine after leaving the research setting. Among 203 former participants followed up an average of nine years later, 25.6% had originally received ketamine at the NIMH. Those who had received ketamine were significantly more likely to have used ketamine or esketamine afterward. However, receiving ketamine at the NIMH was not linked to higher rates of suicide attempts, psychiatric hospitalizations, dissociation, hallucinations, or attempts to obtain non-prescribed ketamine. Participants who used ketamine or esketamine after discharge reported more depressive symptoms. No symptoms indicating abuse were reported. The findings highlight the need for long-term monitoring of patients receiving rapid-acting antidepressants.
Ketamine rapidly reduces depressive symptoms in treatment-resistant depression but does not improve working memory, attention, or concentration. In a crossover trial, 21 individuals with treatment-resistant depression (14 with bipolar disorder, 7 with major depressive disorder) received ketamine or placebo infusions. Brain activity measured by magnetoencephalography during a working memory task showed increased gamma power in the parieto-occipital junction and decreased gamma power in the posterior superior temporal sulcus and inferior frontal gyrus after ketamine compared to placebo. These distinct gamma power changes in brain regions linked to attention and working memory suggest that ketamine alters neural activity without improving cognitive performance, highlighting the need for further research into its neurobiological mechanisms.