I completed a first class BSc in Psychology at the University of Exeter and an MSc with distinction in Clinical Mental Health Sciences at University College London. I have experience of working with individuals with mental health and substance use disorders in a secondary mental health care setting. I am currently a third year PhD student within the Psychopharmacology and Addiction Research Centre at the University of Exeter. My PhD research focuses on the role of ruminative thinking in initiating and maintaining alcohol use disorders and exploring rumination as a target of psychological and pharmacological treatment approaches. My research projects to date include examining the impact of acute alcohol consumption on rumination in the laboratory and in naturalistic settings among hazardous drinking populations, and using experience sampling methods to investigate the relationship between daily ruminative thinking and subsequent craving and alcohol consumption in hazardous drinkers and those with alcohol use disorders. I am also interested in research exploring the use of ketamine for the treatment of substance use disorders, and I have recently completed a systematic review on this.
PhD Symposium: Examining rumination and anhedonia as mechanisms of ketamine treatment for alcohol use disorders
Background: Ketamine is an NMDA receptor antagonist that has been consistently demonstrated to have rapid antidepressant effects. In a recent clinical trial, ketamine was associated with increased abstinence from alcohol at 3- and 6-months follow-up compared to placebo among individuals with alcohol use disorders. A number of mechanisms have been proposed to underlie ketamine’s therapeutic benefits on increasing abstinence from alcohol. Here, we aimed to explore transdiagnostic processes such as anhedonia and rumination as mechanisms of ketamine treatment for alcohol use disorders.
Methods: Data was collected as part of the Ketamine for the Reduction of Alcoholic Relapse (KARE) trial. 96 participants were randomised to receive either three infusions of ketamine (0.8mg/kg IV) or saline placebo (50 ml saline in 0.9% IV) combined with relapse prevention focused psychotherapy or alcohol education. Psychological measurements were taken at baseline, at the end of treatment and at 3- and 6-months’ follow-up using multiple questionnaires. Exploratory factor analysis (EFA) was used to identify latent factors across these questionnaires.
Results: EFA with 61 items revealed a three-factor structure, accounting for 41.5% of total variance. The factors were named respectively as State Anxiety, Rumination and Anhedonia. Mixed measures ANOVAs indicated a significant reduction in rumination and anhedonia in the ketamine group compared to placebo at 3 months follow-up. However, these changes were not found to mediate ketamine’s effects on percentage of abstinent days at 6 months follow-up. Additionally, we found no impact of ketamine on state anxiety with a mixed measures ANOVA.
Discussion: Our results corroborate previous findings that ketamine can significantly alleviate symptoms of anhedonia and rumination. However, changes in these transdiagnostic processes were not found to be related to the drinking outcomes. Limitations of the study which may explain the lack of mediation, including the minimal depression levels in the sample, are discussed.
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