March 2026
Depression
What March 2026's 25 new studies found, synthesized from the papers below. All Depression research →
The synthesis
Synthesized from 25 studies in the library · AI-generated, grounded in the abstracts below
Found by searching the library for Depression, major depressive disorder, MDD, depressive disorder, treatment-resistant depression, then ranked by relevance.
Research in March 2026 confirms that both psilocybin and esketamine are effective for treatment-resistant depression (TRD), with psilocybin showing response rates around 50% in a triple-blind trial and esketamine showing 70% response in real-world settings. However, the evidence is limited by small sample sizes, open-label designs, and a lack of long-term durability data.
Confidence in the evidence
Low-Moderate- Only one triple-blind RCT (n=144) on psilocybin for TRD; other psilocybin studies are manuals or reviews.
- Esketamine evidence includes a small real-world cohort (n=50) and a systematic review, but no large RCTs in this set.
- Results are consistent in direction (positive) across studies, but sample sizes are small and designs vary.
- No long-term follow-up beyond 6 months in most studies; durability of effects is unclear.
How we rate confidence
Confidence reflects the strength of the underlying evidence, not whether the result is favorable. It weighs the number and size of studies, their design (randomized trials count for more than observational or single-case work), how consistently they point the same way, and their risk of bias.
Tiers run from Insufficient to High. High is rare in this field: small, early, or open-label studies land lower even when their direction is encouraging.
Evidence by study
Direction is each study's finding relative to your question: Supports, Opposes, No effect, Mixed, or Unclear.
| Study | Design | Sample size | Direction | Finding |
|---|---|---|---|---|
| Efficacy and Safety of Psilocybin in Treatment-Resistant Major Depression 2026 | RCT | 144 | Supports | Psilocybin 25 mg showed a 50% response rate on HAMD17 at week 6, significantly higher than placebo. |
| GH001 vs Placebo in Patients With Treatment-Resistant Depression 2026 | RCT | 81 | Supports | Inhaled mebufotenin (GH001) showed significant improvement in MADRS scores from baseline to day 8 compared to placebo. |
| Esketamine nasal spray for treatment-resistant depression: A retrospective multicenter real-world cohort study on effectiveness and suicidal outcomes. 2026 | observational | 50 | Supports | Esketamine nasal spray led to significant improvements in MADRS and SDS scores, with 70% response and 68% remission rates at last observation. |
| Cognitive Effects of Esketamine in Treatment-Resistant Depression: A Systematic Review. 2026 | systematic review | Supports | Esketamine was not associated with cognitive deterioration and showed improvements in attention and processing speed. | |
| Neuroimaging insights from Wistar-Kyoto rats under chronic mild stress: morphological and metabolic brain correlates of treatment-resistant depression. 2026 | preclinical | Unclear | WKY/CMS rats showed reduced glutamate and glutamine in PFC and hippocampus, consistent with TRD metabolic changes. | |
| [Esketamine alleviates depression-like behaviors in mice with chronic restraint stress by activating glutamatergic neurons in the medial prefrontal cortex]. 2026 | preclinical | 150 | Supports | Esketamine reduced depressive-like behaviors in CRS mice and activated glutamatergic neurons in mPFC. |
| Enhancing cGMP signaling with psilocybin reduces head twitch and restructures the synaptic proteome while maintaining antidepressant response 2026 | preclinical | Supports | Combining psilocybin with a PDE9 inhibitor reduced head twitch response while maintaining antidepressant effects. | |
| Effect of Ketamine on Reward Processing in Depressive Disorders: A Systematic Review of Neuroimaging Studies 2026 | systematic review | 623 | Supports | Ketamine modulated fronto-striatal and limbic networks, associated with rapid antidepressant effects. |
| Ketamine as a Rapid-Acting Antidepressant: A Scoping Review of Mechanisms and Efficacy in Treatment-Resistant Depression. 2026 | review | Supports | Ketamine shows rapid antidepressant effects via glutamatergic modulation and synaptic plasticity. | |
| Underlying Mechanisms of the Treatment Efficacy of (R, S)‐Ketamine for Post‐Traumatic Stress Disorder and Depression: A Review 2026 | review | Supports | Ketamine and its stereoisomers show efficacy for TRD and PTSD, with (R)-ketamine having lower abuse potential. | |
| Neural signaling mechanisms in depression: bridging classical monoamine hypotheses, animal models, and emerging antidepressant strategies 2026 | review | Supports | Ketamine and psychedelics challenge monoamine models, highlighting glutamatergic and plasticity mechanisms. | |
| Psilocybin: Chemical Foundations and Emerging Therapeutic Potential. 2026 | review | Supports | Psilocybin shows therapeutic potential for TRD and MDD, with FDA breakthrough therapy designations. | |
| Therapist Manual for Psilocybin-Assisted Therapy of Treatment-Resistant Major Depression 2026 | theoretical | Unclear | A therapist manual for psilocybin-assisted therapy was developed for the EPIsoDE trial. | |
| Intranasal esketamine: real-world clinical practice in treatment-resistant depression and factors associated with treatment response. 2026 | observational | Supports | Intranasal esketamine showed real-world effectiveness in TRD, with factors associated with treatment response. | |
| Fast-acting approaches for treatment-resistant depression: real-world comparative effectiveness of Intranasal Esketamine versus accelerated rTMS. 2026 | observational | Supports | Intranasal esketamine and accelerated rTMS both showed effectiveness in TRD. | |
| Intranasal esketamine for treatment-resistant depression: real-world effectiveness in electroconvulsive therapy non-responders 2026 | observational | 60 | Supports | Intranasal esketamine reduced MADRS scores from 33.9 to 15.7 at 6 months, with no difference in ECT non-responders. |
| Efficacy and Safety of Intranasal Esketamine in Treatment-Resistant Depression with Comorbid Autism Spectrum Disorder: Three Case Reports. 2026 | case series | 3 | Supports | Intranasal esketamine improved depressive symptoms in three young adults with autism and TRD. |
| Evaluation of Current Evidence on the Efficacy of Esketamine in Treating Substance-Use Disorders in Patients With Treatment-Resistant Depression (TRD): A Narrative Review 2026 | review | Supports | Esketamine may reduce drug-seeking behavior and cravings in TRD patients with comorbid SUDs. | |
| Ketamine for comorbid treatment-resistant depression and substance use disorders: balancing risks and opportunities 2026 | theoretical | Mixed | Ketamine is effective for TRD but has abuse potential; risks and benefits must be weighed in SUD patients. | |
| Preventing Depression through Selflessness: Effects and Mechanisms of Attentional vs. Deconstructive Meditation in a Three–Arm Randomized Controlled Trial 2026 | RCT | 147 | Supports | Both focused-attention and self-inquiry meditation reduced depressive symptoms compared to wait-list control. |
| Role of Anesthesia in ECT for Major Depressive Disorder. 2026 | review | Unclear | Ketamine anesthesia in ECT is associated with longer seizures and possibly better outcomes, but evidence is limited. | |
| Explainable AI framework for psilocybin depression treatment optimization 2026 | theoretical | Unclear | An XAI framework was developed for optimizing psilocybin treatment protocols using simulated data. | |
| Intranasal 5-MeO-DMT Concomitant with SSRI for Treatment-Resistant Depression: A Proof-of-Concept Trial. 2026 | RCT | Unclear | A proof-of-concept trial of intranasal 5-MeO-DMT with SSRI for TRD was conducted. | |
| Depression Among Hmong Shamans: A Qualitative Exploration of Beliefs and Experiences 2026 | qualitative | 12 | Unclear | Hmong shamans understand depression through cosmology and spiritual imbalance, and use culturally-rooted coping strategies. |
| IMPLEMENTATION OF GOOD AND STRONG CULTURE FOR ISLAMIC MINDFULNESS THERAPY AS AN ALTERNATIVE TO OVERCOMING ANXIETY AND DEPRESSION 2026 | qualitative | Supports | Islamic mindfulness therapy integrating local culture improved resilience and emotional management in young Muslims. |
Psilocybin 25 mg showed a 50% response rate on HAMD17 at week 6, significantly higher than placebo.
RCT Sample size: 144
Inhaled mebufotenin (GH001) showed significant improvement in MADRS scores from baseline to day 8 compared to placebo.
RCT Sample size: 81
Esketamine nasal spray led to significant improvements in MADRS and SDS scores, with 70% response and 68% remission rates at last observation.
observational Sample size: 50
Esketamine was not associated with cognitive deterioration and showed improvements in attention and processing speed.
systematic review
WKY/CMS rats showed reduced glutamate and glutamine in PFC and hippocampus, consistent with TRD metabolic changes.
preclinical
Esketamine reduced depressive-like behaviors in CRS mice and activated glutamatergic neurons in mPFC.
preclinical Sample size: 150
Combining psilocybin with a PDE9 inhibitor reduced head twitch response while maintaining antidepressant effects.
preclinical
Ketamine modulated fronto-striatal and limbic networks, associated with rapid antidepressant effects.
systematic review Sample size: 623
Ketamine shows rapid antidepressant effects via glutamatergic modulation and synaptic plasticity.
review
Ketamine and its stereoisomers show efficacy for TRD and PTSD, with (R)-ketamine having lower abuse potential.
review
Ketamine and psychedelics challenge monoamine models, highlighting glutamatergic and plasticity mechanisms.
review
Psilocybin shows therapeutic potential for TRD and MDD, with FDA breakthrough therapy designations.
review
A therapist manual for psilocybin-assisted therapy was developed for the EPIsoDE trial.
theoretical
Intranasal esketamine showed real-world effectiveness in TRD, with factors associated with treatment response.
observational
Intranasal esketamine and accelerated rTMS both showed effectiveness in TRD.
observational
Intranasal esketamine reduced MADRS scores from 33.9 to 15.7 at 6 months, with no difference in ECT non-responders.
observational Sample size: 60
Intranasal esketamine improved depressive symptoms in three young adults with autism and TRD.
case series Sample size: 3
Esketamine may reduce drug-seeking behavior and cravings in TRD patients with comorbid SUDs.
review
Ketamine is effective for TRD but has abuse potential; risks and benefits must be weighed in SUD patients.
theoretical
Both focused-attention and self-inquiry meditation reduced depressive symptoms compared to wait-list control.
RCT Sample size: 147
Ketamine anesthesia in ECT is associated with longer seizures and possibly better outcomes, but evidence is limited.
review
An XAI framework was developed for optimizing psilocybin treatment protocols using simulated data.
theoretical
A proof-of-concept trial of intranasal 5-MeO-DMT with SSRI for TRD was conducted.
RCT
Hmong shamans understand depression through cosmology and spiritual imbalance, and use culturally-rooted coping strategies.
qualitative Sample size: 12
Islamic mindfulness therapy integrating local culture improved resilience and emotional management in young Muslims.
qualitative
Points of agreement
- Psilocybin and esketamine both show efficacy for treatment-resistant depression.
- Ketamine and esketamine have rapid antidepressant effects mediated by glutamatergic and synaptic plasticity mechanisms.
- Real-world studies confirm esketamine effectiveness in TRD, including in ECT non-responders.
- Psilocybin's antidepressant effects are maintained even when psychedelic effects are attenuated (preclinical).
Conflicts
- One study suggests ketamine has abuse potential in SUD patients, while another finds it reduces drug-seeking behavior.
- The psilocybin trial (n=144) used an active placebo, while the GH001 trial (n=81) used placebo; comparability is limited.
- Real-world esketamine response rates (70%) are higher than the psilocybin trial response rate (50%), but populations differ.
Gaps
- Long-term durability of psilocybin and esketamine effects beyond 6 months is not well studied.
- No large-scale RCTs directly comparing psilocybin, esketamine, and other interventions for TRD.
- Blinding in psychedelic trials is challenging; most studies are open-label or have active placebos.
- Data on esketamine in special populations (e.g., autism, SUD) are limited to small case series or reviews.
- Preclinical findings on mechanisms (e.g., PDE9i combination) have not been translated to human trials.