The effectiveness of intravenous ketamine in adults with treatment-resistant major depressive disorder and bipolar disorder presenting with prominent anxiety: Results from the Canadian Rapid Treatment Center of Excellence

Background: Individuals meeting criteria for treatment-resistant depression (TRD) are differentially affected by high levels of anxiety symptoms.

Aims: There is a need to identify the efficacy of novel rapid-onset treatments in adults with mood disorders and comorbid anxious-distress.

Methods: This study included patients with treatment-resistant major depressive disorder (MDD) or bipolar disorder (BD) who were receiving intravenous (IV) ketamine treatment at a community-based clinic.Anxious-distress was proxied using items from the Quick Inventory of Depressive Symptomatology–Self Report 16-item (QIDS-SR 16 ) and Generalized Anxiety Disorder 7-item (GAD7) scales. The difference in QIDS-SR 16 total score, QIDS-SR 16 suicidal ideation (SI) item and GAD7 score were analyzed between groups.

Results: A total of 209 adults with MDD ( n = 177) and BD ( n = 26) were included in this analysis. From this sample, 94 patients (mean = 45 ± 13.9 years) met the criteria for anxious-distress. Individuals meeting the criteria for anxious-distress exhibited a significantly greater reduction in QIDS-SR 16 total score following four infusions ( p = 0.02) when compared with patients not meeting the anxious-distress criteria. Both anxious-distressed and low-anxiety patients exhibited a significant reduction in SI ( p < 0.0001) following four infusions.Finally, there was a significantly greater reduction in anxiety symptoms in the anxious-distress group compared with the non–anxious distress group following three ( p = 0.02) and four infusions ( p < 0.001).

Conclusion: Patients with TRD and prominent anxiety receiving IV ketamine exhibited a significant reduction in depressive, SI and anxiety symptoms.