Table 1.
Study characteristics (k = 6)
| Study | Design | Population | Intervention(s) | Primary Findings |
|---|---|---|---|---|
| Diazgranados et al., 2010 | Crossover RCT | TRBD (n = 17) | Racemic, adjunctive ketamine: 0.5 mg/ kg IV on 2 test days 2 weeks apart vs. placebo | 71% (vs. 6%) responded to ketamine (vs. placebo) during the trial on the MADRS. Dissociative symptoms occurred at the 40-minute mark. One participant in each group developed manic symptoms. |
| Zarate et al., 2012 | Crossover RCT | TRBD (n = 15) | Racemic, adjunctive ketamine: 0.5 mg/ kg IV on 2 test days 2 weeks apart vs. placebo | 79% (vs. 0%) responded to ketamine (vs. placebo) during the trial on the MADRS. Dissociative symptoms occurred at the 40-minute mark. |
| Rybakowski et al., 2013 | Open-label, single-arm trial | TRBD (n = 25) | Racemic, adjunctive ketamine: 0.5 mg/ kg IV, single dose | Using the HDRS, there were 13 ketamine responders and 8 remitters after 7 and 14 days, respectively. Serum NGF, NT3, NT4, and GDNF did not significantly change. |
| Permoda-Osip et al., 2014 | Open-label, single-arm trial | TRBD (n = 42) | Racemic, adjunctive ketamine: 0.5 mg/ kg IV, single dose | HDRS scores reduced significantly after 24 hours (from 22.6±5.1 hours to 15.6±7.4 hours), 7 days (to 13±7 days), and 14 days (to 11.8±7.8 days). |
| Grunebaum et al., 2017 | Parallel RCT | Non-TRBD (n = 16) | Racemic, adjunctive ketamine: 0.5 mg/ kg IV, single dose vs. midazolam 0.02 mg/kg IV | HDRS and SSI scores reduced by approximately 6 points each in the ketamine group, but the differences were not statistically significant. |
| Zheng et al., 2020 | Open-label, single-arm trial | TRBD (n = 19) | Racemic, adjunctive ketamine: 0.5 mg/ kg IV, 6 doses over 12 days | Rates of response and remission were 73.7% and 63.2% at the study end. There were no significant dissociative and psychotomimetic symptoms on the CADSS or BPRS. |
Abbreviations: BPRS, Brief Psychiatric Rating Scale; CADSS, Clinician-Administered Dissociative States Scale; GDNF, glial-derived neurotrophic factor; HDRS, Hamilton Depression Rating Scale; IV, intravenous; MADRS, Montgomery-Åsberg Depression Rating Scale; NGF, nerve growth factor; NTF3, neurotrophin-3; NTF4, neurotrophin-4; RCT, randomized controlled trial; SSI, Scale for Suicidal Ideation; TRBD, treatment-resistant bipolar depression.