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

Herein we evaluate the impact of COVID-19 restrictions on antidepressant effectiveness of intravenous (IV) ketamine in adults with treatment-resistant depression (TRD). We conducted a case series analysis of adults with TRD (n = 267) who received four ketamine infusions at an outpatient clinic in Ontario, Canada, during COVID-19 restrictions (from March 2020 - February 2021; n = 107), compared to patients who received treatment in the previous year (March 2019 - February 2020; n = 160). Both groups experienced significant and comparable improvements in depressive symptoms, suicidal ideation, and anxiety with repeated ketamine infusions. Effectiveness of IV ketamine was not attenuated during the COVID-19 period.

The effectiveness of repeated intravenous ketamine on depressive symptoms, suicidal ideation and functional disability in adults with major depressive disorder and bipolar disorder: Results from the Canadian Rapid Treatment Center of Excellence.

BACKGROUND: The effectiveness, tolerability, and safety of intravenous (IV) ketamine in adults with treatment resistant depression (TRD) receiving care in real-word settings is insufficiently characterized. Herein, results from a naturalistic, retrospective study are presented from a Canadian outpatient IV ketamine clinic. METHODS: Adults (N = 213; Mage = 45) with Major Depressive Disorder or Bipolar Disorder, with a minimum of Stage 2 antidepressant resistance, received IV ketamine at a community-based multi-disciplinary clinic. The primary outcome measure was change from baseline to post-infusion 4 on the Quick Inventory for Depression Symptomatology-Self Report-16 (QIDS-SR16; n = 190). Secondary measures included QIDS-SR16-measured response and remission rates, changes from baseline to endpoint in Generalized Anxiety Disorder-7 Scale (GAD-7; n = 188) and the Sheehan Disability Scale (SDS; n = 168). RESULTS: Significant improvement in total depressive symptoms severity (p < 0.0001) was observed after four infusions of IV ketamine 0.5-0.75 mg/kg. Moreover, the response rate (QIDS-SR16 total score change ≥ 50%) was 27% and remission (QIDS-SR16 total score ≤5) rate was 13%. Patients receiving IV ketamine exhibited anxiolytic effects (p < 0.0001,), improved overall psychosocial function (p < 0.0001), and reduced suicidal ideation (p < 0.0001). Compared to the baseline infusion, dissociation severity significantly reduced in subsequent infusions. LIMITATIONS: This was a naturalistic, retrospective study, without a control group. CONCLUSIONS: IV ketamine was safe, well-tolerated, and effective at improving depressive, anxiety, and functional impairment symptoms in a well-characterized cohort of adults with TRD.