Real-world effectiveness of repeated ketamine infusions for treatment resistant depression during the COVID-19 pandemic

Introduction

Since March 2020, public health measures to limit SARS-CoV-2 transmission—including closure of non-essential services, prolonged social isolation and quarantines—have been widely implemented and are associated with increased risk of adverse mental health outcomes, particularly among people with pre-existing mood disorders. Social support is identified as a key determinant of resilience and positive outcomes in mood disorders, and pandemic-related stressors such as loneliness and circadian disruption might plausibly attenuate the effectiveness of antidepressant treatments. Intravenous (IV) ketamine is a rapid-acting treatment option for adults with treatment-resistant depression (TRD) and has been shown to reduce suicidal ideation quickly, but its outcomes in the context of pandemic restrictions had not been assessed. Rosenblat and colleagues set out to compare real-world antidepressant effectiveness of a standard course of repeated IV ketamine infusions delivered in an outpatient clinic before versus during the COVID-19 pandemic in Ontario, Canada. The study aimed to determine whether public health restrictions and related changes in social interaction altered clinical response to ketamine in adults with TRD who received four infusions over approximately two weeks.