OPEN Foundation

Day: 22 January 2021

Prolonged ketamine infusion modulates limbic connectivity and induces sustained remission of treatment-resistant depression

Abstract

Ketamine produces a rapid antidepressant response in over 50% of adults with treatment-resistant depression. A long infusion of ketamine may provide durable remission of depressive symptoms, but the safety, efficacy, and neurobiological correlates are unknown. In this open-label, proof-of-principle study, adults with treatment-resistant depression (N = 23) underwent a 96-h infusion of intravenous ketamine (0.15 mg/kg/h titrated toward 0.6 mg/kg/h). Clonidine was co-administered to reduce psychotomimetic effects. We measured clinical response for 8 weeks post-infusion. Resting-state functional magnetic resonance imaging was used to assess functional connectivity in patients pre- and 2 weeks post-infusion and in matched non-depressed controls (N = 27). We hypothesized that responders to therapy would demonstrate response-dependent connectivity changes while all subjects would show treatment-dependent connectivity changes. Most participants completed infusion (21/23; mean final dose 0.54 mg/kg/h, SD 0.13). The infusion was well tolerated with minimal cognitive and psychotomimetic side effects. Depressive symptoms were markedly reduced (MADRS 29 ± 4 at baseline to 9 ± 8 one day post-infusion), which was sustained at 2 weeks (13 ± 8) and 8 weeks (15 ± 8). Imaging demonstrated a response-dependent decrease in hyperconnectivity of the subgenual anterior cingulate cortex to the default mode network, and a treatment-dependent decrease in hyperconnectivity within the limbic system (hippocampus, amygdala, medial thalamus, nucleus accumbens). In exploratory analyses, connectivity was increased between the limbic system and frontal areas, and smaller right hippocampus volume at baseline predicted larger MADRS change. A single prolonged infusion of ketamine provides a tolerated, rapid, and sustained response in treatment-resistant depression and normalizes depression-related hyperconnectivity in the limbic system and frontal lobe. ClinicalTrials.gov : Treatment Resistant Depression (Pilot), NCT01179009.

Siegel, J. S., Palanca, B., Ances, B. M., Kharasch, E. D., Schweiger, J. A., Yingling, M. D., Snyder, A. Z., Nicol, G. E., Lenze, E. J., & Farber, N. B. (2021). Prolonged ketamine infusion modulates limbic connectivity and induces sustained remission of treatment-resistant depression. Psychopharmacology, 238(4), 1157–1169. https://doi.org/10.1007/s00213-021-05762-6

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Clinically meaningful changes on depressive symptom measures and patient-reported outcomes in patients with treatment-resistant depression

Abstract

Objective: To use the Clinical Global Impression-Severity (CGI-S) scale to estimate clinically meaningful and clinically substantial changes as measured using the Montgomery-Åsberg Depression Rating Scale (MADRS), the Sheehan Disability Scale (SDS), and the Patient Health Questionnaire-9 (PHQ-9) in patients with treatment-resistant depression (TRD).

Methods: Pooled data were derived from two 4-week, randomized, active-controlled studies evaluating esketamine nasal spray (ESK) plus oral antidepressant (OAD) or OAD plus placebo nasal spray (PBO) in adults with TRD (N = 565). CGI-S, MADRS, SDS, and PHQ-9 scores were obtained at baseline and over 4 weeks of treatment. In this post hoc analysis, change scores on the MADRS, SDS, and PHQ-9 that corresponded to a clinically meaningful (1-point) or clinically substantial (2-point) change on the CGI-S scale were identified.

Results: Clinically meaningful changes in CGI-S scores after 28 days corresponded to 6-, 4-, and 3-point changes from baseline on the MADRS, SDS, and PHQ-9, respectively. Similarly, a 2-point CGI-S score change (clinically substantial change) corresponded to a 12-, 8-, and 6-point change on the MADRS, SDS, and PHQ-9, respectively. The proportion of patients showing substantial clinical improvement in the ESK plus OAD group versus the OAD plus PBO group after 28 days of treatment favored ESK plus OAD: 69.0% vs 55.3% (MADRS), 64.5% vs 48.9% (SDS), and 77.1% vs 64.7% (PHQ-9).

Conclusion: We provide a basis for identifying clinically meaningful and clinically substantial changes as assessed with commonly used outcome measures for depression to facilitate the translation of clinical trial results into clinical practice.

Turkoz, I., Alphs, L., Singh, J., Jamieson, C., Daly, E., Shawi, M., Sheehan, J. J., Trivedi, M. H., & Rush, A. J. (2021). Clinically meaningful changes on depressive symptom measures and patient-reported outcomes in patients with treatment-resistant depression. Acta psychiatrica Scandinavica, 143(3), 253–263. https://doi.org/10.1111/acps.13260

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