The effect of ketamine on anhedonia: improvements in dimensions of anticipatory, consummatory, and motivation-related reward deficits

Anhedonia is a common, persistent, and disabling condition. However, available therapeutics primarily focus on the reduction of depressive and negative symptoms rather than amelioration of deficits in positive affect. As such, extant drug treatments remain largely ineffective in treating symptoms of anhedonia. Ketamine is a rapid-acting and novel therapeutic treatment for treatment-resistant depression, which has also been demonstrated to attenuate symptoms of anhedonia. However, the literature on the anti-anhedonic effects of ketamine is limited—especially within independent dimensions of this symptom domain. Herein, this review examined the impact of ketamine treatment on anhedonia and its dimensions on anticipatory, consummatory, and motivation-related reward deficits. Overall, the findings have shown a trend towards symptom reduction and/or improvements in anhedonia and their respective subdomains, in both human and preclinical studies, as well as its potential to provide additional benefit in reducing suicidality and improving quality-of-life. Although further research is required in understanding the long-term efficacy and mechanism, ketamine may provide an effective and rapid-acting therapeutic in an otherwise unmet domain.