Ketamine Infusion (KI) in Treatment Resistant Depression (TRD): Retrospective Clinical Data Analysis

Objective: The aim of this paper is to present the clinical data analysis results from a service delivering ketamine infusion, repetitive transcranial magnetic stimulation (rTMS) and electroconvulsive therapy for people with treatment resistant depression (TRD). Methods: The study was a retrospective investigation of routinely collected data on patients receiving ketamine infusion between 2017 and 2019. Measures used were the clinician-rated Clinical Global Impression (CGI) and self-reported Beck Depression Inventory (BDI) and Quick Inventory of Depressive Symptomatology (QIDS-SR). The outcome data of 28 patients with TRD were analysed. A minimum course of treatment was defined as three ketamine infusions. Results: Response combined with partial response, response, and remission rates respectively were 42.3%, 23.1% and 4.2% for the BDI; 18.2%, 9.1% and 0% for the QIDS-SR; 50%, 18.2% and 4.6% for the CGI. There was a statistically significant improvement on the BDI with a medium effect size (0.63). There was not a significant improvement in the CGI or QIDS-SR. Conclusions: The results show a mixed picture the impact ketamine on symptoms of depression in TRD over the course of multiple infusions. The results need to be viewed in the context of clinical outcome data collection: outcome scores are taken prior to treatment and so are at a point when ketamine is not having an active effect. The findings can inform the availability of ketamine infusion as a treatment option for TRD where treatment adhering to national guidelines has not succeeded. A qualitative investigation of the experience of people receiving ketamine would provide further insights.