American Journal of Psychiatry
August 28, 2013
James W. Murrough, Dan V. Iosifescu, Lee C. Chang et al.
1,207 citations
A single intravenous infusion of ketamine produced greater improvement in depression severity 24 hours later than the active placebo midazolam in patients with treatment-resistant major depression. In a randomized controlled trial of 73 participants, the ketamine group scored 7.95 points lower on the Montgomery-Åsberg Depression Rating Scale than the midazolam group. Response rates were 64% for ketamine and 28% for midazolam, with an odds ratio of 2.18 favoring ketamine. The findings support NMDA receptor modulation as a mechanism for rapid improvement in severe, chronic depression, though more information on durability and safety is needed before clinical use.
World Psychiatry
September 15, 2023
Roger S McIntyre, Mohammad Alsuwaidan, Bernhard T Baune et al.
712 citations
At least 30% of people with depression meet the common definition of treatment-resistant depression (TRD): inadequate response to two or more antidepressants despite adequate trials and adherence. Many cases are actually pseudo-resistant due to insufficient treatment or non-adherence. No consensus definition with proven predictive utility for clinical decisions exists, leading to varied prevalence estimates and inconsistent care. Intravenous ketamine and intranasal esketamine are effective for TRD. Some second-generation antipsychotics (e.g., aripiprazole, quetiapine XR) help as adjuncts in partial responders, but only the olanzapine-fluoxetine combination has been studied in FDA-defined TRD. Repetitive transcranial magnetic stimulation and electroconvulsive therapy are established effective interventions. Evidence for extending trials, switching, or combining antidepressants is mixed, and manual-based psychotherapies are not effective alone but help when added to antidepressants.
JAMA Psychiatry
April 16, 2014
Adriana Feder, Michael K. Parides, James W. Murrough et al.
618 citations
A single intravenous dose of ketamine (0.5 mg/kg) rapidly reduced posttraumatic stress disorder (PTSD) symptom severity more than the active placebo midazolam in patients with chronic PTSD. Twenty-four hours after infusion, the ketamine group showed a mean reduction of 12.7 points on the Impact of Event Scale-Revised compared to midazolam. Ketamine also lessened comorbid depressive symptoms and improved overall clinical presentation. The treatment was generally well tolerated without persistent dissociative symptoms. These results suggest ketamine may offer a novel pharmacologic approach for chronic PTSD, though replication is needed.
American Journal of Psychiatry
April 8, 2016
Jaskaran Singh, Maggie Fedgchin, Ella Daly et al.
530 citations
In adults with treatment-resistant depression, intravenous ketamine (0.5 mg/kg) given two or three times per week produced a substantial and similar reduction in depression scores over 15 days compared to placebo. The twice-weekly ketamine group showed an average 18.4-point drop on the Montgomery-Åsberg Depression Rating Scale, versus 5.7 points for placebo; the thrice-weekly group showed a 17.7-point drop, versus 3.1 points for placebo. Headache, anxiety, dissociation, nausea, and dizziness were common side effects, but dissociative symptoms were temporary and lessened with repeated doses.
Depression and Anxiety
March 25, 2014
Rebecca B Price, Dan V. Iosifescu, James W. Murrough et al.
342 citations
A single subanesthetic dose of intravenous ketamine reduced explicit suicidal thoughts and implicit associations between self and escape in adults with treatment-resistant major depression more than the active placebo midazolam. Twenty-four hours after infusion, 53% of ketamine-treated patients scored zero on all three explicit suicide measures, compared with 24% of the midazolam group. The reductions in explicit suicidal cognition were largest in those with higher baseline suicidal thoughts and were partly explained by decreases in other depressive symptoms. The findings suggest ketamine may offer rapid relief from suicidal cognition beyond what a psychoactive placebo provides.
Psychological Medicine
August 12, 2015
James W. Murrough, Laili Soleimani, Kaitlin E. DeWilde et al.
297 citations
A single infusion of ketamine, compared to midazolam as an active placebo, did not reduce suicidal ideation scores on the Beck Scale for Suicidal Ideation at 24 hours in patients with mood and anxiety disorders who were at elevated risk for suicidal behavior. A significant difference favoring ketamine emerged at 48 hours, but the effect was no longer significant by the end of 7 days. The intervention was well tolerated with no dropouts during the primary assessment period. The findings support the safety and tolerability of ketamine for suicidal ideation but larger studies are needed.
The International Journal of Neuropsychopharmacology
March 17, 2009
Sanjay J. Mathew, James W. Murrough, Marije Aan Het Rot et al.
295 citations
A single intravenous dose of ketamine (0.5 mg/kg) produced rapid antidepressant effects in patients with treatment-resistant major depression, with 65% responding at 24 hours and 54% at 72 hours. Pretreatment with lamotrigine did not reduce ketamine's mild side effects or improve its antidepressant action. In a subsequent randomized trial, riluzole (100-200 mg/day) failed to prevent relapse over 32 days; 80% of riluzole-treated patients relapsed versus 50% on placebo, leading to early termination. Ketamine appears well-tolerated and rapidly effective, but better strategies to sustain its benefits are needed.
The International Journal of Neuropsychopharmacology
October 8, 2013
Colin N. Haile, James W. Murrough, Dan V. Iosifescu et al.
251 citations
In patients with treatment-resistant depression, ketamine increased blood levels of brain-derived neurotrophic factor (BDNF) in those who responded to the drug, compared to non-responders, 240 minutes after infusion. Higher BDNF levels were strongly linked to lower depression scores at multiple time points up to 72 hours. No such associations appeared in patients given the anesthetic midazolam. The findings support BDNF as a marker of ketamine's antidepressant effects.
The Journal of Clinical Psychiatry
September 2, 2014
Le-Ben Wan, Cara F. Levitch, Andrew M. Perez et al.
232 citations
Ketamine given intravenously at 0.5 mg/kg over 40 minutes was safe and well tolerated in a large group of patients with treatment-resistant depression. Across 205 infusions in 97 participants, the antidepressant response rate was 67%. Only about 2% of infusions were stopped due to adverse effects, and the overall dropout rate was 3%. Common temporary side effects in the first four hours included drowsiness, dizziness, poor coordination, blurred vision, and feeling strange or unreal. About one third of participants had changes in blood pressure or heart rate. There were small but significant increases in psychotomimetic and dissociative symptoms, but no lasting psychotic effects, medical complications, or increased substance use among those followed long-term.
Australian & New Zealand Journal of Psychiatry
November 15, 2019
Katrina Witt, Jennifer Potts, Anna A.m. Hubers et al.
203 citations
A single infusion of ketamine may reduce suicidal thoughts in people with treatment-resistant depression within four hours, and the effect can last up to 72 hours. The analysis combined 15 randomized controlled trials with 572 participants, mostly with mood disorders. At four hours after infusion, suicidal ideation scores dropped significantly (standardized mean difference -0.51), and the reduction persisted through 72 hours (standardized mean difference -0.57 to -0.63 at different intervals) but not beyond. Results varied widely across studies, and evidence quality was moderate to low. There were almost no data on whether ketamine prevents actual suicide attempts or self-harm. Further trials are needed to confirm these findings and find ways to sustain the anti-suicidal effect.
Translational Psychiatry
March 21, 2017
Drew D. Kiraly, Sarah R. Horn, Nicholas T. van Dam et al.
182 citations
Patients with treatment-resistant depression (TRD) show elevated levels of the pro-inflammatory cytokine interleukin-6 compared to healthy controls, supporting the immune hypothesis of depression. Analysis of 41 cytokines, chemokines, and growth factors in blood samples from 26 healthy controls and 33 unmedicated TRD patients revealed a unique pattern of increased inflammatory mediators, chemokines, and colony-stimulating factors. Following a single intravenous infusion of ketamine (0.5 mg/kg), several cytokines showed transient changes, but none correlated with treatment response. Low pretreatment levels of fibroblast growth factor 2 were associated with ketamine treatment response, suggesting novel treatment targets for TRD patients with dysregulated immune functioning.
Translational Psychiatry
February 17, 2015
James W. Murrough, Katherine A. Collins, Jessica Fields et al.
111 citations
A single low dose of ketamine increases brain activity in the right caudate when people with treatment-resistant depression view happy faces, reversing a baseline deficit compared with healthy volunteers. Twenty patients with treatment-resistant depression not taking other antidepressants underwent fMRI before and 24 hours after receiving intravenous ketamine (0.5 mg per kg of body weight). Twenty matched healthy controls were scanned once. Before ketamine, depressed patients showed reduced neural responses to happy faces in the right caudate. After ketamine, responses to happy faces increased in a similar region. Greater connectivity of the right caudate during positive emotion perception was linked to greater improvement in depression severity. No effects were seen for sad faces.
The Journal of Clinical Psychiatry
May 26, 2020
George I. Papakostas, Naji C. Salloum, Rebecca S. Hock et al.
107 citations
Adjunctive intranasal esketamine is more effective than placebo for treating major depressive disorder. Pooling five randomized, double-blind trials with 774 patients, esketamine outperformed placebo on depression rating scale score change, response, and remission. The effect was statistically significant across different study samples and baseline antidepressant regimens. Esketamine appears to be an effective treatment strategy for patients who are treatment-resistant or acutely suicidal.
Molecular Psychiatry
September 7, 2022
Rebecca B Price, Nicholas Kissel, Andrew Baumeister et al.
80 citations
Ketamine given intravenously rapidly reduces depressive symptoms, with effects lasting at least a week. In an analysis of 17 randomized controlled trials with 809 participants, the benefit over placebo was larger for patients who had already failed two or more prior antidepressant trials. However, no patient-level clinical or demographic characteristics—such as age, sex, or diagnosis—could predict who would respond best, limiting the ability to personalize ketamine prescriptions. The findings confirm ketamine's broad effectiveness for depression but show that precision medicine approaches cannot yet guide treatment decisions.
JAMA Network Open
June 3, 2024
Manish Kumar Jha, Samuel T. Wilkinson, Kamini Krishnan et al.
29 citations
In people with treatment-resistant depression who do not have psychosis, intravenous ketamine works as well as electroconvulsive therapy (ECT) overall. Among outpatients with moderately severe or severe depression, ketamine produced greater improvement in depressive symptoms than ECT. In contrast, inpatients with very severe depression improved more with ECT early in treatment, though by the end of the three-week course both treatments were similarly effective. Higher premorbid intelligence and a diagnosis of posttraumatic stress disorder were linked to greater improvement with ECT, but not with ketamine. These findings may help patients and clinicians decide between the two treatments.
Journal of psychopharmacology (Oxford, England)
October 1, 2024
Jessica L Ables, Leah Israel, Olivia Wood et al.
17 citations
Harmine, a component of the hallucinogenic brew ayahuasca, was tested in a phase 1 clinical trial to determine its safety, tolerability, and psychoactive effects when taken alone. Twenty-five healthy adults received single oral doses of 100 to 500 mg of pharmaceutical-grade harmine hydrochloride. The maximum tolerated dose was between 100 and 200 mg, and doses above 2.7 mg/kg caused vomiting, drowsiness, and limited psychoactive effects in 90% of participants. No serious adverse events occurred. Harmine alone can be safely administered at low doses, but higher doses produce dose-limiting side effects and only mild psychoactivity.
American journal of medical genetics. Part B, Neuropsychiatric genetics : the official publication of the International Society of Psychiatric Genetics
June 17, 2025
Clio E Franklin, Murat Altinay, Kala Bailey et al.
2 citations
For treatment-resistant mood disorders, intensive interventions such as electroconvulsive therapy, transcranial magnetic stimulation, ketamine, and esketamine are commonly used, but how genetics influences response to these therapies remains unclear. A review of the current literature finds that most studies have examined single variants in candidate genes, particularly COMT and BDNF, yet none have been consistently reproducible. Genome-wide association studies are few and mostly underpowered, with only one exceeding 1000 participants, yielding few statistically significant single nucleotide polymorphisms outside COMT and BDNF. Large-scale data collection is needed to establish genetic predictors and differentiate responses among treatments, a goal being pursued by the worldwide Gen-ECT-ic consortium.
Psychiatry Research
May 1, 2025
Gerard Sanacora, Brian S. Barnett, Bo Hu et al.
2 citations
Patients with treatment-resistant depression who preferred ketamine over electroconvulsive therapy (ECT) were more likely to respond to treatment, regardless of which treatment they actually received. Matching patients to their preferred treatment improved response rates for ketamine but not for ECT, and reduced adverse events for ECT-treated patients. Ketamine was the more popular choice overall. The findings suggest that aligning treatment with patient preference can influence effectiveness, safety, and possibly adherence, but these effects vary by treatment modality and context.
American Journal of Geriatric Psychiatry
February 24, 2026
Rachel Fremont, Amelia Karim, Tanya Peguero Estevez et al.
1 citation
In an open-label clinical trial, a single intravenous infusion of ketamine (0.5 mg/kg) was safe and well tolerated in 13 patients with mild cognitive impairment and major depressive disorder. No serious adverse events occurred. Depression severity, measured by the Montgomery-Asberg Depression Rating Scale, dropped from a mean of 27.4 before treatment to 5.7 at 24 hours after the infusion—a large-magnitude improvement. For 8 of the 13 patients, this improvement persisted for up to one month, with a mean score of 12.1 and at least a 50% reduction. These findings suggest ketamine may be effective for depression in this population, but larger randomized controlled trials are needed to confirm efficacy and assess cognitive effects.
medRxiv Preprint Server
April 10, 2021
Agnes Norbury, Sarah B. Rutter, Abigail B. Collins et al.
1 citation
preprint
In a small randomized clinical trial, repeated doses of ketamine improved PTSD symptoms more than midazolam. Brain scans showed that symptom improvement was linked to increased communication between the ventromedial prefrontal cortex and amygdala when viewing emotional faces, especially in those who received ketamine. Ketamine-related improvement was also predicted by decreased activity in the dorsal anterior cingulate during emotional conflict and increased resting-state connectivity between the ventromedial prefrontal cortex and anterior insula. Further analysis indicated that ketamine specifically strengthened the prefrontal cortex's ability to inhibit amygdala responses to threatening social cues, suggesting a normalization of brain circuits involved in fear regulation.
Translational Psychiatry
May 12, 2026
Linda Bryant, Laith Alexander, Sergio Mena et al.
A machine-learning model using structural brain scans predicted which adults with treatment-resistant depression would respond to a single ketamine infusion. The model, trained on 99 participants, achieved 72% balanced accuracy in the discovery sample and 60% in two independent groups, with performance dropping to chance in a saline-treated control group. Greater gray matter volume in frontal regions predicted response, while greater cerebellar volume predicted non-response. The findings suggest that pre-treatment brain structure may help guide personalized treatment decisions for ketamine therapy.
The Journal of Clinical Psychiatry
September 3, 2025
Kristina T. Kumpf, Samuel T. Wilkinson, Bo Hu et al.
In a multisite randomized trial comparing cognitive effects of intravenous ketamine and electroconvulsive therapy (ECT) in patients with treatment-resistant depression, those receiving six ketamine treatments showed superior cognitive functioning after a three-week treatment course compared with those receiving nine ECT sessions. No significant differences in cognitive task performance were associated with response to either treatment. Among responders followed for up to six months, no group differences emerged. Subjective memory measures were mixed: both groups improved on the Squire Memory Complaint Questionnaire, with ketamine recipients reporting greater functional gains, while ketamine-treated patients reported improvements on a global self-evaluation of memory but ECT-treated patients reported a decline. Within the ketamine group, improvements in executive functioning and cognitive flexibility survived adjustment for changes in depression, suggesting partial independence of cognitive and mood effects.
The Journal of Clinical Psychiatry
April 2, 2025
Adriana Feder, Oneysha Brown, Sarah B. Rutter et al.
Combining six ketamine infusions with a brief exposure-based psychotherapy, written exposure therapy (WET), produced large and durable reductions in PTSD symptoms for patients with chronic, severe PTSD. In an open-label trial, 13 of 14 patients completed treatment. PTSD symptom severity, measured by the CAPS-5, dropped from an average of 41.6 before treatment to 20.8 at 12 weeks, a large-magnitude improvement. Nine patients (69%) were treatment responders, and eight (61.5%) maintained improvement up to six months. The authors suggest the combined treatment may be effective but call for larger randomized controlled trials to confirm efficacy and synergy.
International Journal of Neuropsychopharmacology
June 1, 2024
Mina M Rizk, James W. Murrough
No Summary
Journal of Affective Disorders
August 15, 2017
James W. Murrough, Elizabeth Wade, Sehrish Sayed et al.
A combination of dextromethorphan and quinidine, given at up to 45/10 mg twice daily for 10 weeks, reduced depression scores in patients with treatment-resistant depression. Twenty patients with unipolar treatment-resistant depression enrolled; six discontinued early. Depression scores on the Montgomery-Asberg Depression Rating Scale dropped by an average of 13 points, and on the Quick Inventory of Depressive Symptomatology by nearly 6 points. Response and remission rates were 45% and 35%, respectively. No treatment-emergent suicidal thoughts, psychosis, or dissociation occurred. The open-label, proof-of-concept design limits conclusions, but results suggest the combination is tolerable and warrants larger placebo-controlled trials.