Can J Psychiatry
October 28, 2025
Jennifer Swainson, Elisa Brietzke, Atul Khullar et al.
2 citations
Interest in psychedelic agents for psychiatric conditions like PTSD, depression, and anxiety has grown, especially with the spread of ketamine clinics. However, the evidence is confusing because there are no standard definitions for what psychotherapy means in these treatments. Studies often fail to distinguish between using a manualized psychotherapy, providing general psychological support, or offering therapy specifically to integrate the drug experience. It is also unclear whether the drug works alone or if the psychedelic experience is needed for therapeutic effect.
Journal of Affective Disorders
September 16, 2025
Sami George Sabbah, Sophie Li, Sabrina Wong et al.
2 citations
Psilocybin is linked to dynamic and temporally distinct neuroplastic changes that are associated with clinical improvement in depression. However, many studies reused overlapping datasets, had high exploratory flexibility, and risk of bias, which limits the generalizability of the results. Future research should use independent datasets, pre-registered imaging endpoints, and longitudinal designs to better understand the mechanisms of psychedelic therapy for depression.
Journal of Affective Disorders
July 23, 2025
Joyce Xu Hao Jin, Heidi Ka Ying Lo, Iris Wai Tung Tsui et al.
2 citations
In people with major depressive disorder (MDD) and bipolar disorder (BD), positive psychological traits such as mindfulness and grit interact with negative affect to influence positive mental health. Over two weeks, 29 people with MDD, 29 with BD, and 30 healthy controls reported their negative affect, pleasure attainment, and meaning in life five times daily. Lower negative affect strengthened the link between mindfulness and meaning in life in the MDD group but not in the BD or control group. Higher grit reduced the harmful effect of negative affect on pleasure attainment in the BD group but not in the other groups. These findings highlight complex relationships between positive traits and mental health in mood disorders.
The Journal of Clinical Psychiatry
July 7, 2025
Angela T H Kwan, Moiz Lakhani, Joshua D. Rosenblat et al.
2 citations
In a global pharmacovigilance analysis of adverse event reports from the World Health Organization's VigiBase database, esketamine was associated with higher reporting odds for suicidal ideation compared to lithium (5.13 times) and fluoxetine (3.34 times), while ketamine showed lower reporting odds for suicidal ideation, suicide attempt, and completed suicide relative to both reference drugs. Both drugs had lower reporting odds for suicide attempts and completed suicides. The authors caution that causality cannot be determined from these observational data.
JAMA Psychiatry
July 1, 2026
Sung Ryul Shim, Hye Su Jeong, Tanner J. Bommersbach et al.
1 citation
A systematic review and meta-analysis of 26 randomized clinical trials with 1,166 patients experiencing a major depressive episode found that intravenous ketamine infusions significantly reduce suicidal and depressive symptoms in the acute phase. A single ketamine infusion lowered suicidal symptoms at 24 hours and at 1 month, and repeated infusions produced similar reductions. Depressive symptoms decreased significantly from 4 hours through 1 week after a single infusion and after repeated infusions. Serious adverse events were unrelated to the interventions, and other side effects were transient. Longer-term outcomes remain unclear.
Expert Opinion on Therapeutic Targets
January 28, 2026
Gia Han Le, Roger S McIntyre
1 citation
Up to half of adults with major depressive disorder who do not respond to two or more standard antidepressants may have treatment-resistant depression (TRD). Low-dose intravenous ketamine, intranasal esketamine, and oral dextromethorphan are the first glutamatergic treatments to work rapidly and robustly for TRD, but their exact mechanisms are unclear. This review integrates evidence that elevated tonic NMDA receptor currents, mainly through NR2C/D subunits, underlie TRD. Ketamine, esketamine, and dextromethorphan selectively dampen these currents to produce rapid and sustained antidepressant effects. Ketamine and esketamine's affinity for NR2A/B subunits likely drives dissociative effects not seen with dextromethorphan. Future drug development should focus on subunit-biased ligands.
Therapeutic Advances in Psychopharmacology
January 1, 2026
Alessandro Cuomo, Roger S McIntyre, Despoina Koukouna et al.
1 citation
Among 45 patients with treatment-resistant depression treated with intranasal esketamine alongside oral antidepressants in a routine clinic, depression severity scores dropped from an average of 40.0 to 22.9 at four weeks and to 9.70 at 52 weeks, with scores remaining near 9-10 at later follow-ups. Eight patients stopped treatment, mostly due to lack of efficacy or side effects. No manic symptoms emerged, and side-effect ratings were low. The findings suggest sustained symptom improvement and a favorable long-term safety profile for those who continued treatment, though the observational design, concurrent treatments, and survivor bias limit the conclusions.
The Canadian Journal of Psychiatry
March 25, 2025
Noah Chisamore, Erica Kaczmarek, Zoe Doyle et al.
1 citation
A single 25 mg dose of psilocybin combined with psychotherapy produced clinically significant reductions in depression, anxiety, and suicidality symptoms over two months in people with treatment-resistant depression. Among 27 participants, those who tapered off antidepressant medications before treatment (n = 18) and those not on antidepressants at screening (n = 9) showed comparable improvements, with no significant differences between groups on clinician-rated depression, self-reported depression, anxiety, or suicidality. The intensity of the psychedelic experience was also similar. These results suggest that tapering antidepressants before psilocybin-assisted psychotherapy may not diminish therapeutic benefits, though further research is needed.
Journal of Pain and Symptom Management
August 1, 2026
Stefan Aguiar, Mary Makarious, Orly Lipsitz et al.
In adults with advanced cancer receiving palliative care, intranasal ketamine was associated with clinically meaningful improvements in existential distress, anxiety, symptom burden, and quality of life. Fifteen participants who completed three doses of ketamine showed improvements exceeding established minimal clinically important differences on measures of anxiety, death and dying distress, overall symptoms, and quality of life. Improvements in existential well-being were larger than those in physical symptoms. Changes in depression did not significantly correlate with changes in existential distress outcomes, suggesting ketamine may have independent effects on multiple dimensions of distress in this population.
Journal of psychopharmacology (Oxford, England)
June 24, 2026
Shreya Vasudeva, Gabrielle F. M. Lovell, Sabrina Wong et al.
Ketamine and its enantiomer esketamine show low risk of abuse, dependence, or misuse when administered under controlled clinical supervision, based on a systematic review of 30 studies (25 clinical and 5 preclinical). Clinical studies found minimal evidence of craving, dose escalation, or illicit use in monitored settings. Preclinical work indicated that (S)-ketamine produces reward-related behaviors, racemic ketamine shows reinforcing effects at higher doses, and (R)-ketamine has minimal reinforcing effects. Abuse risk was identified mainly in case reports lacking proper monitoring. The findings support safe incorporation of ketamine into mood disorder treatment protocols with structured administration and ongoing monitoring.
Clinical Neuropharmacology
June 19, 2026
Isabela Heroiu, Gia Han Le, Maria‐christina Sioufi et al.
Ketamine, an N-methyl-D-aspartate receptor antagonist, consistently and significantly reduced obsessive-compulsive disorder symptom severity by up to 50% to 60% across five studies, though the duration of effects ranged from a few hours to six weeks. Ketamine was generally well tolerated. The review included three randomized controlled trials and two open-label trials with variable routes of administration (intravenous, intramuscular, and oral) and dosing frequencies. Further research is needed to optimize ketamine treatment for sustained symptom reduction.
Clinical Pharmacology & Therapeutics
May 28, 2026
Gia Han Le, Sabrina Wong, Danica E. Johnson et al.
The serotonin 5-HT2B receptor sits at a crossroads between potential antidepressant effects in the brain and serious heart valve risks when activated peripherally. This narrative review of preclinical and clinical literature finds that peripheral activation of 5-HT2B receptors causes valvular heart disease through cell proliferation and scarring, as seen with older drugs like fenfluramine and some dopamine agonists. In the brain, the receptor's effects are mixed: astrocytic activation may support metabolism and plasticity, while neuronal blockade can normalize dopamine and glutamate activity. Several approved antidepressant adjuncts (aripiprazole, brexpiprazole, cariprazine) antagonize this receptor without observed heart valve problems. The authors propose developing centrally selective, periphery-sparing 5-HT2B antagonists for treatment-resistant depression, with early cardiac monitoring to ensure safety.
Research Square
May 27, 2026
Tychique T. Wasolua, Tanner J. Bommersbach, Roger S McIntyre et al.
Ketamine and its S-enantiomer esketamine show both neurotoxic and neuroprotective effects depending on dose, duration, and experimental model. In preclinical studies, high or repeated doses can cause neuronal damage, while lower doses may protect against injury. Human studies are limited but suggest similar potential for harm and benefit. The systematic review highlights the need for careful dosing and monitoring in clinical use, especially for depression treatment.
Journal of Affective Disorders
April 1, 2026
Kayla M Teopiz, Gia Han Le, Sabrina Wong et al.
A systematic review of 13 preclinical studies and 1 human study found that dextromethorphan (DXM), a glutamatergic modulator with antidepressant properties, attenuates reward-seeking behavior in rats, as measured by conditioned place preference and behavioral sensitization. In the single human study involving 20 healthy participants, self-reported drug-liking for DXM (400 mg/70 kg) was significantly lower compared to psilocybin (20 mg and 30 mg) 7 hours after dosing. The review highlights a paucity of human studies and suggests that future research should investigate DXM's effects on reward function using validated paradigms in people with anhedonia.
CNS Spectrums
March 10, 2026
Halima Faisal, Gia Han Le, Angela T H Kwan et al.
Ketamine rapidly alters brain reward circuitry in people with major depressive disorder, particularly in fronto-striatal and limbic networks. In a synthesis of 13 neuroimaging studies involving 623 participants (482 with depression, 141 controls), intravenous ketamine (typically 0.5 mg/kg over 40 minutes) changed resting-state connectivity in ventral striatal-prefrontal and default mode, salience, and executive networks within 2 to 48 hours, with some effects lasting up to 10 days. Task-based imaging showed altered ventral striatal responses during reward anticipation and feedback, and changes in medial prefrontal activity during emotion processing. PET scans indicated increased prefrontal-cingulate metabolism and region-specific serotonin receptor binding changes. Few studies directly measured anhedonia, suggesting the findings reflect broader antidepressant mechanisms.
Psychiatry Research
February 19, 2026
Trisha Menon, Andy Lu, Akhilan Arulmozhi et al.
Ketamine, esketamine, repetitive transcranial magnetic stimulation (rTMS), and electroconvulsive therapy (ECT) are associated with reductions in suicidal ideation in people with major depressive disorder. The strongest evidence from randomized controlled trials supports rapid, short-term effects, particularly for ketamine and esketamine. Further research is needed to characterize the durability of these antisuicidal effects and to determine whether reductions in suicidal ideation translate into reduced severity of suicidal behavior.
Journal of Affective Disorders
February 12, 2026
Erica Kaczmarek, Nelson Rodriguez, Noah Chisamore et al.
Anhedonia, a core symptom of depression that often resists standard treatments, may be reduced by psilocybin-assisted psychotherapy (PAP). In a secondary analysis of a randomized, waitlist-controlled trial, 30 adults with treatment-resistant depression (major depressive disorder or bipolar II disorder) received one 25 mg dose of oral psilocybin plus psychotherapy. Anhedonia severity, measured by the Snaith-Hamilton Pleasure Scale, decreased significantly at the 2-week primary endpoint, with clinically meaningful improvements persisting at 3 and 6 months. The analysis adjusted for sex and age. These preliminary results suggest PAP could be a promising intervention for anhedonia in treatment-resistant depression, though larger placebo-controlled trials are needed to confirm the findings and clarify underlying mechanisms.
Pharmacopsychiatry
February 5, 2026
Tianyi Xu, Sabrina Wong, Gia Han Le et al.
Lysergic acid diethylamide and 3,4-methylenedioxymethamphetamine activate the 5-hydroxytryptamine 2B receptor, a pathway known to cause drug-induced valvular heart disease. This systematic review of 17 studies found no research on psilocybin, dimethyltryptamine, or mescaline. Both lysergic acid diethylamide and 3,4-methylenedioxymethamphetamine show high or moderate affinity for this receptor and promote signaling linked to fibrotic changes in heart valve tissue. In vivo studies confirm serotonin-induced valvulopathy, and chronic 3,4-methylenedioxymethamphetamine use has been associated with valve abnormalities in humans. No clinical cases of lysergic acid diethylamide-induced valvulopathy have been reported, but preclinical data suggest potential for fibrotic signaling under sustained exposure. Preliminary evidence supports the need for cardiac safety monitoring in psychedelic research.
General Hospital Psychiatry
January 1, 2026
Gabrielle F. M. Lovell, Shreya Vasudeva, Diana Orsini et al.
Ketamine, an anesthetic also used for mood and anxiety disorders, may cause mild, temporary elevations in liver enzymes, but serious liver damage appears rare. A systematic review of 13 studies (5 randomized trials, 3 observational studies, and 5 case reports) involving 1,017 patients—mostly with major depressive disorder or bipolar disorder—found 75 mild liver enzyme elevations across trials, with only a few cases of impaired liver function. No cases met Hy's Law criteria for severe drug-induced liver injury. Case reports described more severe liver issues that improved with dose reduction or stopping treatment. Routine liver monitoring during ketamine treatment remains advisable.
Progress in Neuro-psychopharmacology and Biological Psychiatry
November 22, 2025
Shakila Meshkat, Noah Chisamore, Zoe Doyle et al.
A single dose of psilocybin was linked to small, temporary gains in processing speed and executive function in people with treatment-resistant depression. These cognitive improvements seemed unrelated to mood changes but did not consistently surpass the improvements expected from simply retaking the tests. The findings underscore the need for larger, controlled studies to determine whether psilocybin genuinely enhances cognition or if the observed changes stem from practice effects or mood shifts.
Neuroendocrinology
October 30, 2025
Sabrina Wong, Gia Han Le, Jens Uhlig et al.
Blocking NMDA receptors improves the function and survival of pancreatic alpha and beta cells, which may help explain why certain NMDA antagonists like ketamine, esketamine, and dextromethorphan have antidepressant effects and could also address metabolic problems often seen in depression. The findings suggest a shared mechanism linking mood regulation and pancreatic hormone control. More research is needed on how low doses of these drugs affect pancreatic function and delta cells.
European neuropsychopharmacology : the journal of the European College of Neuropsychopharmacology
February 1, 2025
Danica E. Johnson, Nelson B Rodrigues, Sydney Weisz et al.
Depression with co-occurring posttraumatic stress disorder (PTSD) leads to more severe symptoms and poorer response to standard treatments. In a retrospective analysis of 134 patients with treatment-resistant depression, four ketamine infusions (0.5-0.75 mg/kg) reduced depressive symptoms equally in those with and without comorbid PTSD; no significant group-by-time interaction was found. PTSD symptoms also significantly improved across all symptom clusters, with moderate to large effect sizes. Ketamine shows promise as an effective intervention for this hard-to-treat population, though future randomized trials should explore factors driving improvement and long-term outcomes.
Journal of Psychiatric Research
June 1, 2026
Kyle Valentino, Hana Ballum, William Cheung et al.
About 80% of people with major depressive disorder (MDD) report insomnia. This systematic review examined how glutamatergic modulators, especially ketamine, affect sleep in preclinical and clinical studies. Preclinical work showed ketamine alters EEG delta power during NREM sleep and normalizes clock suppressor gene expression, while esketamine enhances delta power but arketamine does not. mGlu2/3 activators reduce REM sleep. Clinical studies indicate that improved sleep can mediate ketamine's antidepressant effects in MDD. The authors suggest that sleep-related mechanisms are potential targets for depression treatment.
Journal of Affective Disorders
February 1, 2026
Kayla M Teopiz, Sabrina Wong, Gia Han Le et al.
Reward processing disruptions in major depressive disorder (MDD) may relate to altered frontostriatal brain activity. Glutamatergic modulators might improve reward function. This systematic review examined 11 fMRI studies testing glutamatergic agents—ketamine (9 studies), nitrous oxide (1), and memantine (1)—on frontostriatal activity in people with MDD or healthy controls. Preliminary evidence suggests intravenous ketamine may alter functional connectivity in striatal regions, potentially relevant to improved reward function in treatment-resistant depression. More research is needed on how these modulators affect reward-related brain structures, the timing of effects, and baseline characteristics predicting antidepressant response.
Expert Opinion on Drug Metabolism & Toxicology
January 1, 2026
Yang Jing Zheng, Christine E. Dri, Sabrina Wong et al.
Dextromethorphan/bupropion (DXM/BUP) received breakthrough FDA approval in August 2022 as a rapid-acting antidepressant. DXM/BUP is a noncompetitive NMDA receptor antagonist and sigma-1 receptor agonist, combined with bupropion, a norepinephrine/dopamine reuptake inhibitor and CYP2D6 inhibitor. DXM alone has long been misused due to its metabolism into the psychoactive metabolite dextrorphan (DXO). The article discusses the pharmacodynamics and pharmacokinetics of DXM and DXO, highlights the abuse potential of DXM alone, and presents preclinical, clinical, and pharmacovigilance findings that support reduced abuse liability of DXM/BUP. The formulation demonstrates clinically meaningful improvement within one week of initiation. Given its safety, efficacy, and novelty, this glutamatergic modulator is a promising candidate for global approval. Future research should examine its potential in bipolar depression and trauma-associated MDD.