Mental Health Clinical Trials 2026: Depression, Anxiety, and Psychiatric Studies

Treatment-Resistant Depression: The Ketamine and Esketamine Era

Treatment-resistant depression (TRD) — defined as failure to respond to at least two adequate antidepressant trials — affects an estimated 30% of people with major depressive disorder. Esketamine (Spravato, Janssen) nasal spray became the first FDA-approved TRD treatment with a novel mechanism in 2019, achieving response rates of ~54% versus ~31% for placebo in the Phase 3 TRANSFORM-2 trial. Since approval, real-world evidence has confirmed durability and safety, and IV ketamine infusions are widely used off-label at specialized ketamine clinics despite the lack of a specific FDA approval for depression.

In 2026, trials are pushing esketamine earlier in the treatment algorithm (ESCAPE-TRD, evaluating esketamine in patients who have failed just one antidepressant), exploring maintenance dosing strategies (weekly vs. biweekly), and combining esketamine with psychotherapy. Zuranolone (Zurzuvae, neuroactive steroid GABA-A receptor positive allosteric modulator) achieved FDA approval in 2023 for major depressive disorder and postpartum depression as a 14-day oral treatment course. SHORELINE long-term data show sustained response with on-demand retreatment, and trials are evaluating zuranolone for bipolar depression, premenstrual dysphoric disorder, and treatment-resistant anxiety.

Psilocybin: Phase 3 Trials for Depression and Anxiety

Psilocybin — the active compound in psychedelic mushrooms — has shown remarkable results in Phase 2 trials. The landmark COMPASS Phase 2b trial of COMP360 (synthetic psilocybin, 25mg single dose with psychological support) in TRD showed a 29.1% remission rate versus 7.6% for placebo at 3 weeks — with effects lasting months. A Johns Hopkins Phase 2 trial showed that two psilocybin sessions produced response rates equivalent to 6 weeks of SSRI therapy in treatment-resistant major depression. Phase 3 trials (COMP360 and psilocybin from Usona Institute's EPIC-MDD program) are now enrolling patients in the US, UK, Canada, and Australia.

For anxiety disorders, psilocybin Phase 2 data show significant reductions in anxiety severity in patients with cancer-related existential distress, generalized anxiety disorder, and OCD. Phase 3 trials for cancer-related anxiety (NYU/Hopkins) and GAD (atai Life Sciences' MINDSET Phase 2b progressing to Phase 3) are enrolling in 2026. The regulatory pathway is complex — psilocybin remains Schedule I in the US, but the FDA has granted Breakthrough Therapy Designation to COMP360 for TRD and to Usona's psilocybin for major depressive disorder, providing a defined path to approval.

PTSD: MDMA-Assisted Therapy and Stellate Ganglion Block

MDMA-assisted therapy (MDMA-AT) for PTSD — developed by MAPS (Multidisciplinary Association for Psychedelic Studies) — produced PTSD remission in 67% of participants versus 32% for therapy plus placebo in the Phase 3 MAPP1 trial. While the FDA did not approve MDMA-AT in 2024, citing the need for an additional trial, the science was not in question — it was regulatory and manufacturing concerns. The MAPP3 follow-on trial is now enrolling, with Lykos Therapeutics working to address FDA concerns. MDMA-AT is approved and available in Australia since February 2023, and Phase 3 results from the Australian program will inform the FDA resubmission.

Stellate ganglion block (SGB) — an anesthetic injection near the stellate ganglion in the neck, hypothesized to reset autonomic dysregulation in PTSD — showed significant PTSD symptom reduction in the SPRINT Phase 2 (70% response rate vs. 20% sham). The VALOR Phase 3 (stellate ganglion block vs. sham, active-duty military) is now enrolling. Ibogaine (a psychedelic derived from African iboga plant) is in Phase 1/2 for veteran treatment-resistant PTSD at Stanford, following extraordinary open-label data (87% no longer meeting PTSD diagnosis criteria after a single treatment) from a Stanford Medicine-MAPS collaboration.

Neurostimulation: TMS Innovation and Deep Brain Stimulation

Transcranial magnetic stimulation (TMS) is FDA-approved for major depression, OCD, and anxious depression, and repetitive TMS (rTMS) to the left dorsolateral prefrontal cortex is standard in TRD after antidepressant failure. The most significant advance is accelerated TMS (aTMS) — delivering 10 sessions in a single day rather than over 6 weeks, using the SAINT (Stanford Accelerated Intelligent Neuromodulation Therapy) protocol targeting the subgenual cingulate cortex connected area of the DLPFC. Phase 2 data showed 78.6% remission rate in TRD at one month — extraordinary compared to standard TMS outcomes. The SAINT Phase 3 (Magnus Medical, now commercialized as SMA-TMS) is under active FDA review.

Deep brain stimulation (DBS) for TRD — targeting the subcallosal cingulate (Brodmann Area 25) or the habenula — has a complex history after the BROADEN trial failed, likely due to inadequate patient selection and stimulation parameter optimization. Next-generation closed-loop DBS systems (Medtronic Summit RC+S, Abbott Infinity) that adapt stimulation parameters based on real-time neural recording are in Phase 2 at UCSF, Emory, and Mayo Clinic with more rigorous patient phenotyping using neuroimaging biomarkers. Vagus nerve stimulation (VNS) for TRD (Neurex NCP System) received expanded access designation after pooled analysis of 500+ patients showed significant long-term response rates.

Eligibility and How to Find Psychiatric Trials

Psychiatric trial eligibility typically requires a formal DSM-5 diagnosis confirmed by a structured clinical interview (MINI, SCID), specific severity thresholds on validated scales (e.g., MADRS ≥ 20 for MDD, PCL-5 ≥ 31 for PTSD, HAM-A ≥ 18 for anxiety), documented prior treatment failures for TRD studies, and stability of current medications. Exclusion criteria commonly include active suicidal ideation with intent/plan, current psychosis, active substance use disorder, cardiovascular contraindications (for stimulant-adjacent drugs), and pregnancy. Washout periods from prior psychiatric medications (typically 2–5 half-lives) are often required before trial dosing begins.

ClinicalTrials.gov searches by condition ("Major Depressive Disorder," "Post-Traumatic Stress Disorder," "Generalized Anxiety Disorder") with "Recruiting" status yield hundreds of options. The NIMH clinical trials portal (clinicaltrials.nimh.nih.gov) lists NIH-funded psychiatric studies. MAPS Public Benefit Corporation (maps.org), the Usona Institute (usonainstitute.org), and COMPASS Pathways (compasspathways.com) each maintain trial registries for their psychedelic-assisted therapy programs. Many psychiatric trials offer compensation for participation, given the typically intensive visit schedules.

Key Takeaways

• Psilocybin Phase 3 trials (COMP360, Usona EPIC-MDD) are enrolling patients with treatment-resistant major depressive disorder following Phase 2 remission rates of 29% versus 7.6% for placebo — with effects lasting months after a single session.
• The SAINT protocol (accelerated TMS, 10 sessions in one day) showed 78.6% remission in TRD Phase 2 — the Phase 3 SMA-TMS trial is under FDA review and could transform TMS access and effectiveness.
• MDMA-assisted therapy for PTSD achieved 67% remission in Phase 3; the MAPP3 follow-on trial is enrolling to address FDA resubmission requirements.
• Ibogaine for veteran PTSD shows extraordinary open-label results (87% no longer meeting PTSD criteria); Phase 1/2 trials are underway at Stanford, with Phase 3 planning dependent on regulatory framework clarification.
• Eligibility for most psychiatric trials requires formal DSM-5 diagnosis, validated scale severity scores, and documented prior treatment failures — having organized treatment history records significantly accelerates the screening process.