September 16, 2021
2 minutes to read
Source / Disclosures
Disclosures: Di Vincenzo does not report any relevant financial information. Please see the study for relevant financial information from all other authors.
In adults with treatment-resistant depression, ketamine monotherapy significantly reduced suicidal ideation compared to adjunct ketamine, according to a retrospective study conducted in Journal of Psychiatric Rresearch.
“Ketamine has been almost exclusively studied as an add-on antidepressant to other antidepressants, most often monoaminergic agents such as SSRIs,” Joshua D. Di Vincenzo, the University of Toronto University Health Network and the Brain and Cognition Discovery Foundation and the Canadian Center of Excellence for Rapid Treatment (CRTCE), and colleagues wrote. “Due to the lack of high-quality clinical data on the safety and efficacy of ketamine as antidepressant monotherapy, the majority of clinicians continue to prescribe ketamine to patients as long as they remain on a stable dose of one or more antidepressants for the duration of treatment.
Researchers analyzed data from 220 adults with treatment-resistant depression (TRD) who received four to six IV ketamine infusions for major depressive disorder at CRTCE between August 2018 and May 2021.
They classified 39 participants (17.7%) not currently using other antidepressants, except psychostimulants and sedatives, as the monotherapy group and 181 participants (82.3%) using at least one other antidepressant. as a backup group.
Participants reported thoughts of suicide and the overall severity of depressive symptoms at baseline and after four infusions; anxiety and functional impairment were reported at baseline for 10 patients, after the third infusion for seven and after the fourth for seven others. If Rapid inventory of depressive symptoms – Self-report 16 items (QIDS-SR16) scores for overall symptoms did not improve after two infusions, the dosage was reduced from 0.5 mg / kg of actual body weight to 0.75 mg / kg. This has mainly happened in younger patients.
The monotherapy group had a significantly greater reduction in their mean QIDS-SR16 sub-score for SI (0.91 point, SD = 0.9) than the adjunct therapy group (0.37 point, SD = 0.8). There was no significant difference in improvement between the monotherapy and the add-on groups for anxiety, functional disorders or general depressive symptoms.
“It is important to note that the reference QIDS-SR16 The SI sub-scores were significantly higher in the monotherapy group, therefore a greater decrease on the QIDS-SR16 One can expect an SI in this group compared to the booster group, ”noted Di Vincenzo and his colleagues.
In both groups, ketamine infusion had a strong and significant effect on overall depressive symptoms and anxiety, and a significant average effect on suicidal ideation and functional disturbances.
Limitations included retrospective design, no controls, use of a TRD population, and incomplete data due to dropouts and participants not completing assessments. Di Vincenzo and colleagues have indicated that larger study populations are needed and suggested characterizing patients who will benefit from monotherapy.
“Future research should focus on determining which patients are more likely (or less likely) to benefit from combination therapy versus monotherapy in people with MDD,” they wrote. In addition, whether a specific combination of ketamine and monoaminergic-based antidepressant is optimal also awaits empirical confirmation.