In recent times, ketamine has gained significant attention in clinical research, particularly for its potential to treat major depressive disorder. However, the mechanisms underlying ketamine’s...Show moreIn recent times, ketamine has gained significant attention in clinical research, particularly for its potential to treat major depressive disorder. However, the mechanisms underlying ketamine’s antidepressant effects are unclear. Previous research has noted that ketamine influences heart rate variability (HRV). Several studies have found ketamine to decrease HRV, while one study observed an increase. It is uncertain whether this is a general effect of ketamine on HRV or whether this was found in individuals because vulnerability to depression strengthened this relationship. In line with this, prior literature established a relationship between HRV and vulnerability to depression. Thus, the current study aims to examine whether ketamine decreases HRV in a healthy (unmedicated) population. Additionally, it is the aim to investigate whether this effect is moderated by a cognitive vulnerability to develop depression. Fifteen female participants, aged 18 to 28 years of age, were analysed using heart rate variability measures and the Leiden Index of depression sensitivity (LEIDS-R). A paired t-test revealed that ketamine significantly decreased HRV 30-40 minutes after infusion. However, vulnerability to depression was not found to significantly moderate the relationship between ketamine and HRV. These findings contribute to the mixed literature on ketamine’s effects on HRV, suggesting variations between healthy and depressed populations. Future research aimed at replicating these findings, exploring cognitive vulnerability in individuals who were once depressed but recovered, and examining the long-term effects of ketamine on HRV is imperative.Show less