Monthly research recap
Ketamine research: September 2026
What September 2026's 25 new studies found, synthesized from the papers below. All Ketamine research →
The synthesis
Synthesized from 25 studies in the library · AI-generated, grounded in the abstracts below
Found by searching the library for Ketamine, racemic ketamine, arketamine, R-ketamine, then ranked by relevance.
Research indexed in September 2026 continued to support ketamine as a rapid-acting antidepressant in treatment-resistant depression, with response rates reported up to about 70% at 24 hours and onset around 110 minutes, but the benefit is typically short-lived (roughly 1-2 weeks) and head-to-head evidence against ECT is inconsistent, with pooled response and remission showing no significant difference amid high heterogeneity. Beyond depression, small and mostly preliminary studies reported signals in alcohol use disorder, smoking cessation, and adolescent/young-adult ketamine-assisted psychotherapy, while biomarker and neuroimaging predictors remain exploratory and no peripheral biomarker is yet clinically usable. The main caveats are small samples, post hoc or open-label designs, and short follow-up; chronic recreational misuse was consistently linked to serious multi-organ toxicity.
Evidence by study
Direction is which way each study's own result points, not our rating of the study.
What the directions mean
- Supports:
- the study found the intervention worked, or its hypothesis held.
- Opposes:
- it found the opposite, no benefit or a harm.
- No effect:
- no significant difference either way.
- Mixed:
- effects in both directions within the same study.
- Unclear:
- the abstract does not report a direction.
| Study | Design | Sample size | Direction | Finding |
|---|---|---|---|---|
| KETAMINE VERSUS ELECTROCONVULSIVE THERAPY FOR SEVERE TREATMENT-RESISTANT DEPRESSION: A SYSTEMATIC REVIEW AND META-ANALYSIS OF EFFICACY, SPEED OF RESPONSE, COGNITIVE OUTCOMES, AND SAFETY 2026 | systematic review and meta-analysis | 1388 | Mixed | Pooled response and remission did not differ significantly between intravenous ketamine and ECT, but heterogeneity was high and largely attributable to one large trial; omitting it produced a significant ECT advantage, and the authors argue the relative advantage depends on illness severity, setting, psychotic features, and age. |
| No Heavy Drinking Days and Percentage of Days Abstinent in a Randomized Trial of Adjunctive Ketamine for Alcohol Use Disorder: Secondary Analysis of the KARE Trial 2026 | post hoc secondary analysis of a 2x2 factorial RCT | 96 | Supports | Ketamine plus mindfulness-based psychological support yielded 78.5% versus 57.8% days abstinent over weeks 17-24 and a 55% relative reduction in heavy drinking days, measured 4-6 months after a 4-week course. |
| Multimodal predictors of response to intravenous ketamine in treatment-resistant depression: toward personalized treatment in major depressive and bipolar disorders. 2026 | systematic review | 150 | Unclear | Identifies candidate predictors of intravenous ketamine response across clinical phenotype, inflammatory and neuroplastic biomarkers, metabolic factors, genetics, neurophysiology, and cognition, and argues most predictors remain exploratory and need prospective validation. |
| Symptom-level and network analyses of ketamine treatment in treatment-resistant depression: A pooled analysis of two randomized controlled trials. 2026 | post hoc analysis of pooled RCTs | 132 | Supports | Ketamine 0.5 mg/kg produced broad early symptom improvement, with adjusted control-minus-ketamine differences at 240 minutes of about 1.1 points on apparent sadness, pessimistic thoughts, and suicidal thoughts, and all four symptom domains differing at 240 minutes and day 2; exploratory network associations were sensitive to reporting thresholds. |
| Ketamine-enhanced psychotherapy for smoking cessation: A pilot study of feasibility, safety, and clinical outcomes. 2026 | open-label pilot study | 7 | Supports | Three weekly intramuscular ketamine sessions (0.71 mg/kg) with motivational enhancement therapy were feasible and well tolerated, with decreased cigarette consumption and nicotine craving but stable withdrawal symptoms, dependence severity, and motivation to quit. |
| Subacute effects of ketamine on neural correlates of reward processing 2026 | single-blind placebo-controlled crossover | 28 | No effect | At about 5 hours after 0.5 mg/kg intravenous ketamine, no significant modulation of brain activation during a monetary incentive delay task was detected in ROI or whole-brain analyses despite measurable subjective drug effects. |
| Ketamine for Treatment-Resistant Depression in Adolescents: Hope or Risk? 2026 | narrative review | Mixed | Concludes ketamine shows short-term efficacy in adolescent treatment-resistant depression, often within 24 hours, but effects are generally short-lived, and argues use should remain limited to specialized settings pending long-term safety and efficacy data. | |
| Peripheral Biomarkers of Response to Ketamine and Esketamine Treatment in Unipolar Depressive Disorder—A Scoping Review 2026 | systematic review (scoping) | 46 | Unclear | Across 46 studies, the most examined peripheral biomarkers were BDNF, inflammatory markers (notably IL-6, TNF-alpha, IL-10, IL-8), and kynurenine pathway metabolites, but results were inconsistent and no biomarker is yet sufficient for clinical implementation. |
| Real-World Therapeutic Use of Ketamine in Clinical and Non-Clinical Settings: A Cross-Sectional Survey 2026 | observational cross-sectional survey | 460 | Mixed | Ketamine was rated similarly and highly effective for mood symptoms by clinical and non-clinical users (mean 83.3 vs 81.2 on a 0-100 scale), while non-clinical users had higher odds of reporting long-term hallucinations (OR 2.58, 95% CI 1.08-6.31). |
| The Era of Rapid-Acting Antidepressants: Clinical Insights Into Ketamine, Esketamine, and Scopolamine 2026 | systematic review | 7 | Supports | Reports that intravenous ketamine (0.5 mg/kg over 40 minutes) had onset around 110 minutes with response rates up to 70% at 24 hours but limited duration of 1-2 weeks, and that intranasal esketamine plus oral antidepressants reduced MADRS scores over four weeks and lowered relapse risk (HR 0.49); scopolamine was considered still experimental. |
| Feasibility and tolerability of virtual reality during esketamine treatment: A pilot study. 2026 | pilot feasibility and tolerability study | 26 | Mixed | Patients commonly reported auditory (33%) and visual (52%) discomfort during ketamine treatment and most were open to virtual reality; among five patients who used VR during an esketamine session, glasses wearers had difficulty and reported nausea, and all showed reduced altered-state scores on the 5D-ASC. |
| Reply to ‘Methodological concerns and interpretative limitations of assessing subjective effects of ketamine’ 2026 | commentary | Unclear | Argues that variation in accompanying psychotherapy and in subjective-effect questionnaires across studies may partly explain treatment differences observed in a meta-analysis of subjective effects and therapeutic outcomes, and calls for standardized multidimensional measures. | |
| Matters arising: Methodological concerns and interpretative limitations of assessing subjective effects of ketamine 2026 | commentary | Unclear | Raises methodological concerns about a meta-analysis of subjective effects, including inconsistencies in study design, flaws in comparing correlation coefficients, and discrepancies in reported results, and calls for more standardized methodologies. | |
| S-propargyl-L-cysteine attenuates ketamine induced schizophrenia-like behaviors and neuroinflammation in mice via inhibition of NF-κB/NLRP3 inflammasome-mediated pyroptosis. 2026 | preclinical animal study | Supports | S-propargyl-L-cysteine reversed ketamine-induced hyperactivity and anxiety, improved working memory and sensorimotor gating, and prevented hippocampal neuronal loss, effects attributed to restoration of the CSE/H2S pathway, maintenance of mBDNF, and inhibition of NF-kappaB/NLRP3-mediated pyroptosis. | |
| Low-dose ketamine tilts the cortical excitation--inhibition balance irrespective of systemic physiological response 2026 | single-blind placebo-controlled crossover | 25 | Supports | Low subanesthetic ketamine flattened the aperiodic EEG exponent (a shift toward excitation) and raised heart rate and blood pressure, while propofol produced opposite effects; the cardiovascular response did not mediate the cortical excitation-inhibition shift. |
| Modulation of GABA and glutamate by ketamine in depression: A systematic review and meta-analysis of magnetic resonance spectroscopy studies. 2026 | systematic review and meta-analysis | 11 | No effect | Meta-analyses of 11 magnetic resonance spectroscopy studies found no statistically significant ketamine-related alterations in GABA, glutamate, or Glx levels, which the authors attribute to methodological heterogeneity rather than a true absence of effect. |
| Implementation and Preliminary Evaluation of an Intravenous Ketamine Protocol for Psychiatric Conditions in Medical and Surgical Units: A One-Year Pilot Study. 2026 | feasibility study | 16 | Supports | A capped-rate IV ketamine protocol (0.5-1.0 mg/kg, infusion rate capped at 5 mcg/kg/min) was feasibly delivered on general medical and surgical floors without additional staffing or care escalations; among 14 patients treated for depression, 12 improved, five met response thresholds, and three met remission thresholds. |
| A longitudinal analysis of the clinical practice of ketamine assisted psychotherapy with adolescents and young adults 2026 | observational cohort (longitudinal case series) | 19 | Supports | Among 19 adolescents and young adults completing three or more ketamine-assisted psychotherapy sessions, BDI-II depression scores declined by an estimated 0.65 points per visit and HAM-A anxiety scores by 0.21 points per visit; about 63% achieved medium or large individual treatment effects on depression and 47% on anxiety, with clinician and patient reports of overall benefit in 68% of cases. |
| A circuit dissection of perception-action decoupling in S-ketamine-induced hallucination-like states. 2026 | preclinical experimental study | Mixed | S-ketamine induced auditory false alarms and behavioral disorganization through dissociable striatal pathways, with aberrant basolateral amygdala-to-caudal striatum recruitment promoting false alarms and medial prefrontal cortex-to-caudal striatum dysregulation generating disorganized action patterns; dexmedetomidine restored pathway-level temporal dynamics. | |
| The K-Hole Collapse: A Systematic Review of Multi-Organ Somatotoxicity and Management Strategies in Chronic Ketamine Misuse 2026 | review | Opposes | Argues that chronic recreational ketamine misuse causes severe multi-organ toxicity including permanent cognitive deficits, ketamine-induced uropathy with hydronephrosis, ketamine cramps from sphincter of Oddi dyskinesia, cardiac remodeling and fibrosis, and hypercapnic respiratory failure, with abstinence as the cornerstone of management and no established pharmacotherapy for cravings. | |
| Samm50 Downregulation-Driven Mitochondrial Dysfunction Triggers Ferroptosis and Contributes to Ketamine-Induced Neurotoxicity and Cognitive Impairment. 2026 | preclinical study (mouse model and cell line) | Opposes | Proposes that ketamine downregulates Samm50, causing mitochondrial dysfunction that triggers ferroptosis via iron accumulation and suppression of GPX4/SLC7A11, and that Samm50 overexpression restores mitochondrial function and ameliorates ferroptosis. | |
| Neuroprotective potential of chrysin against ketamine-induced neurotoxicity: Effects on behavioral changes, oxidative stress, and neuroinflammation. 2026 | controlled experimental animal study | 35 | Mixed | Ten days of ketamine (30 mg/kg i.p.) increased oxidative stress, neuroinflammation, and apoptotic markers and produced neuronal degeneration, necrosis, and vascular hyperemia in cortex and hippocampus; chrysin, particularly at 50 mg/kg, reduced these changes and lowered GFAP and Caspase-3 expression. |
| Esketamine for treatment of depression in Huntington's disease: A case report 2026 | case study | 1 | Mixed | Nasal esketamine was followed by rapid mood improvement, with Beck Depression Inventory score dropping from 29 to 5 after three treatment days, but depression worsened again by three months (BDI 20). |
| Default mode network functional connectivity following treatment with conventional antidepressants and (es)ketamine in major depressive disorder: A systematic review 2026 | systematic review | 19 | Mixed | Conventional antidepressants were associated with heterogeneous changes in default mode network resting-state functional connectivity, some related to clinical improvement, whereas ketamine was mostly associated with reductions in DMN rsFC, particularly DMN-limbic connectivity. |
| Ketamine metabolite HNK ameliorates anhedonia symptom in Alzheimer's disease mice. 2026 | preclinical animal study | Supports | A single dose of the ketamine metabolite (2R,6R)-hydroxynorketamine rapidly reduced anhedonia in APP/PS1 mice, proposed to be mediated by increased prefrontal excitatory/inhibitory ratio, reduced phosphorylated eEF2, and elevated BDNF and GLT-1 expression. |
Points of agreement
- Ketamine produces rapid antidepressant effects in treatment-resistant depression, with onset within hours to about 110 minutes and response rates reported up to roughly 70% at 24 hours.
- Antidepressant benefit is generally short-lived, on the order of 1-2 weeks, and relapse or worsening is commonly reported after the acute phase.
- Predictors of response and peripheral biomarkers remain exploratory and inconsistent, with no marker yet ready for clinical use.
- Chronic recreational ketamine use is associated with serious multi-organ and neuropsychiatric toxicity, and non-supervised use carries additional risk of long-term hallucinations.
- Ketamine's acute subjective and neurophysiological effects are measurable, including dissociative experiences and shifts in cortical excitation-inhibition balance.
Conflicts
- Head-to-head evidence against ECT is discordant: pooled response and remission showed no significant difference, but excluding one large trial produced a significant ECT advantage.
- Ketamine shifted the EEG aperiodic exponent toward excitation in healthy adults, while magnetic resonance spectroscopy meta-analysis found no significant ketamine-related changes in GABA, glutamate, or Glx in depression.
- Ketamine reduced default mode network connectivity in depression, whereas conventional antidepressants showed heterogeneous changes, suggesting distinct network-level effects.
- Self-reported effectiveness was high in both supervised and unsupervised users, yet unsupervised use was associated with higher odds of long-term hallucinations.
Gaps
- Durability of antidepressant response beyond a few weeks, and maintenance strategies to prevent relapse.
- Long-term safety and efficacy in adolescents and young adults, including effects on the developing brain.
- Prospective validation of clinical, biomarker, and neuroimaging predictors of response.
- Standardized, multidimensional measures of subjective experience and consistent control of accompanying psychotherapy.
- Adequately powered trials in substance use disorders, alcohol use disorder, and tobacco use disorder.
- Pharmacotherapy for ketamine cravings and management of chronic misuse toxicity.