Response to ketamine treatment for major depressive disorder not associated with number of psychiatric comorbidities

Abstract

Background: Ketamine has demonstrated efficacy in treating depression unresponsive to traditional interventions and is increasingly utilized in psychiatric practice. However, limited information is available regarding effectiveness in patients with psychiatric comorbidity. The aim of this study is to compare the response of ketamine treatment for depression in patients in a community sample with and without one or more coexisting psychiatric diagnoses. Methods: A retrospective review of medical records from a community ketamine clinic was done. Statistical analyses compared response to intravenous ketamine treatment, as defined by a 50% reduction in Patient Health Questionnaire (PHQ-9) score or final score of <10, in patients with an isolated diagnosis of major depressive disorder (MDD) to those with comorbid generalized anxiety disorder (GAD), obsessive-compulsive disorder (OCD), post-traumatic stress disorder (PTSD) and/or attention-deficit/hyperactivity disorder (ADHD). Results: Data from 129 patient were analyzed (55.8 % female). It was found that the number of psychiatric comorbidities was not associated with ketamine treatment response rate nor mean change in PHQ-9 scores. Limitations: Level of previous treatment resistance was not assessed systematically, and psychiatric interview and some elements of the patients’ care were not standardized, such as treatment schedule and dosing. Conclusions: These findings suggest ketamine may be an effective treatment for depression in appropriate patients with psychiatric comorbidities including GAD, OCD, PTSD and/or ADHD. Additional investigation is warranted to evaluate various patient-level and other factors that may impact ketamine's ability to attenuate depressive symptoms.

Keywords

• Major depressive disorder
• Depression
• Ketamine
• Obsessive-compulsive disorder
• Generalized anxiety disorder
• Post-traumatic stress disorder