Background: Patients unsuccessfully treated by neurostimulation may represent a highly intractable subgroup of depression. While the efficacy of intravenous (IV) ketamine has been established in patients with treatment-resistant depression (TRD), there is an interest to evaluate its effectiveness in a subpopulation with a history of neurostimulation.
Methods: This retrospective, posthoc analysis compared the effects of four infusions of IV ketamine in 135 (x̄ = 44 ± 15.4 years of age) neurostimulation-naïve patients to 103 (x̄ = 47 ± 13.9 years of age) patients with a history of neurostimulation. The primary outcome evaluated changes in depression severity, measured by the Quick Inventory for Depression Symptomatology-Self Report 16-Item (QIDS-SR16). Secondary outcomes evaluated suicidal ideation (SI), anxiety severity, measured by the Generalized Anxiety Disorder 7-Item (GAD-7), and consummatory anhedonia, measured by the Snaith-Hamilton Pleasure Scale (SHAPS).
Results: Following four infusions, both cohorts reported a significant reduction in QIDS-SR16 Total Score (F (4, 648) = 73.4, P < .001), SI (F (4, 642) = 28.6, P < .001), GAD-7 (F (2, 265) = 53.8, P < .001), and SHAPS (F (2, 302) = 45.9, P < .001). No between-group differences emerged. Overall, the neurostimulation-naïve group had a mean reduction in QIDS-SR16 Total Score of 6.4 (standard deviation [SD] = 5.3), whereas the history of neurostimulation patients reported a 4.3 (SD = 5.3) point reduction.
Conclusion: IV ketamine was effective in reducing symptoms of depression, SI, anxiety, and anhedonia in both cohorts in this large, well-characterized community-based sample of adults with TRD.
Rodrigues, N. B., Siegel, A., Lipsitz, O., Cha, D. S., Gill, H., Nasri, F., Simonson, K., Shekotikhina, M., Lee, Y., Subramaniapillai, M., Kratiuk, K., Lin, K., Ho, R., Mansur, R. B., McIntyre, R. S., & Rosenblat, J. D. (2020). Effectiveness of intravenous ketamine in mood disorder patients with a history of neurostimulation. CNS spectrums, 1–7. Advance online publication. https://doi.org/10.1017/S1092852920002187