Arketamine for cognitive impairment in psychiatric disorders

Summary

Cognitive impairment is common in psychiatric disorders like schizophrenia, major depressive disorder, and bipolar disorder, and current medications do not improve it. The drug (R,S)-ketamine, a rapid antidepressant, may improve cognitive impairment in patients with these conditions, even though it causes cognitive impairment in healthy people. Its component arketamine shows more potent antidepressant-like effects than esketamine in rodents and may improve cognitive deficits induced by phencyclidine or maternal immune activation in mice. The article proposes arketamine as a potential treatment for cognitive impairment in psychiatric disorders and discusses the possible role of the gut-microbiome-brain axis.

Study at a glance

Abstract

Cognitive impairment has been observed in patients with various psychiatric disorders, including schizophrenia, major depressive disorder (MDD), and bipolar disorder (BD). Although modern therapeutic drugs can improve certain symptoms (i.e., psychosis, depression) in these patients, these drugs have not been found to improve cognitive impairment. The N-methyl-D-aspartate receptor antagonist (R,S)-ketamine has attracted attention as a rapidly acting antidepressant. In addition to its robust antidepressant effects, (R,S)-ketamine has been suggested to improve cognitive impairment in patients with MDD and BD, despite causing cognitive impairment in healthy control subjects. (R,S)-ketamine is a racemic mixture of equal amounts of (R)-ketamine (or arketamine) and (S)-ketamine (or esketamine). Arketamine has been found to have more potent antidepressant-like actions than esketamine in rodents. Interestingly, arketamine, but not esketamine, has been suggested to improve phencyclidine-induced cognitive deficits in mice. Furthermore, arketamine has been suggested to ameliorate cognitive deficits in rodent offspring after maternal immune activation. In the current article, it is proposed that arketamine has therapeutic potential for treating cognitive impairment in patients with psychiatric disorders. Additionally, the potential role of the gut-microbiome-brain axis in cognitive impairment in psychiatric disorders is discussed.