In July 2023, Australia became the first country in the world to formally recognise psilocybin and MDMA as prescription medicines — a turning point in how science understands the potential of psychoactive compounds to heal minds where conventional treatments have failed.

The Policy: TGA Psychedelic Medicines Decision — February 2023 →

What Australia decided — and what it means

On 3 February 2023, Australia's Therapeutic Goods Administration (TGA) announced that psilocybin (the active compound in magic mushrooms) and MDMA (commonly known as ecstasy) would be rescheduled from Schedule 9 — prohibited substances with no recognised therapeutic use — to Schedule 8, controlled prescription medicines. The change took effect on 1 July 2023.

The approved indications are narrow and deliberate: psilocybin only for treatment-resistant depression (defined as failing at least two different antidepressant medications), and MDMA only for post-traumatic stress disorder where standard therapies have not worked. Only specialist psychiatrists who have registered as Authorised Prescribers under a specific TGA scheme — requiring HREC ethics committee approval and completion of training aligned with the Royal Australian and New Zealand College of Psychiatrists framework — can prescribe these medicines.

This is not recreational legalisation. Treatment occurs in a controlled clinical setting with the psychiatrist present throughout a session lasting eight or more hours. A psilocybin treatment involves a standard 25mg dose; MDMA treatment uses 80–125mg. Both are preceded by preparatory psychotherapy sessions to establish rapport and set therapeutic intentions, and followed by integration therapy the next day to help the patient process the experience. The drug opens a window; the therapy determines what is built inside it.

Our suggestion: New Zealand should be watching this closely

New Zealand has some of the highest rates of depression, anxiety, and suicide in the OECD. Conventional antidepressants fail to produce adequate clinical improvement in approximately 30% of people with major depressive disorder — a group classified as having treatment-resistant depression. For these patients, the options have historically been limited to electroconvulsive therapy, ketamine infusions, or lifelong polypharmacy with diminishing returns.

The evidence for psilocybin-assisted therapy in this group is now compelling. Johns Hopkins researchers found a 75% response rate and 58% remission rate at 12 months after just two supervised sessions — with a five-year follow-up showing 67% remained in remission from a single treatment course. Effect sizes are estimated at approximately four times larger than conventional antidepressants. These are not small, preliminary findings.

New Zealand's Medsafe took a step in the right direction on 19 June 2025, approving Professor Cameron Lacey (University of Otago, Christchurch) as the first NZ psychiatrist able to prescribe psilocybin outside a clinical trial. But only one authorised prescriber for a country of five million is not a system — it is a proof of concept. The cost of a full course of psilocybin therapy in NZ is approximately NZD $20,000, with no Pharmac funding or insurance coverage. Patients are already travelling to Oregon, the Netherlands, and Jamaica for retreats costing $5,000–$15,000 per session. That treatment is available only to those with money. If the evidence holds — and it is increasingly compelling — NZ's public health system needs to build the infrastructure to make this accessible, not leave it to the wealthy.

How psilocybin works — breaking the ruts of rumination

To understand why psilocybin works, you need to understand what depression does to the brain at the network level.

The default mode network (DMN) is the brain's idle circuitry — a connected system spanning the medial prefrontal cortex, posterior cingulate cortex, precuneus, and angular gyrus that activates during self-referential thinking, mind-wandering, and autobiographical memory. In a healthy brain, the DMN switches off when you engage with the external world. In depression, it becomes hyperactive and pathologically self-reinforcing: locked into a loop of negative self-appraisal, replaying the same painful memories and self-critical narratives over and over. This is the neural substrate of rumination.

The problem deepens over time through long-term potentiation (LTP) — the Hebbian principle that neurons that fire together, wire together. Every time the depressed brain runs a rumination loop, the synaptic connections involved become more efficient, the pathway more automatic, harder to interrupt. The groove deepens. This is why depression so often feels like being trapped: the brain has literally become more efficient at generating the very thoughts that cause suffering.

Psilocybin disrupts this system at its source. Its primary mechanism is agonism at the serotonin 5-HT2A receptor, which is concentrated in the cortical layer V pyramidal neurons responsible for top-down, hierarchical signal propagation — the very hardware of the DMN's dominance. The result is a dramatic disruption of the DMN's internal coherence. The brain's activity becomes more diverse, less predictable, more exploratory — what neuroscientists call increased neural entropy.

The critical insight comes from the REBUS model (Relaxed Beliefs Under Psychedelics), developed by Robin Carhart-Harris and cognitive neuroscientist Karl Friston and published in 2019. The brain, they argue, is not a passive receiver of experience but a prediction machine: it constantly generates top-down hypotheses about the world and the self, filtering all incoming data through those prior beliefs. In depression, these priors become pathologically rigid — and resist revision even when contradicted by real experience. Psilocybin temporarily decreases the precision weighting of these priors, loosening their grip on processing. The fixed self-model loses its authority. A window opens.

Robin Carhart-Harris, who founded the world's first Centre for Psychedelic Research at Imperial College London before moving to UCSF, described it this way: "Psilocybin works differently from conventional antidepressants — making the brain more flexible and fluid, and less entrenched in the negative thinking patterns associated with depression." His 2022 Nature Medicine study found that psilocybin therapy produced lasting increases in global brain functional connectivity that persisted for three weeks after treatment ended — long after the drug had cleared. The reorganisation outlasted the pharmacology.

A landmark 2021 Yale study (Shao, Kwan et al., Neuron) added the structural dimension: a single dose of psilocybin produced approximately 10% increases in both the density and size of dendritic spines — the structural basis of synaptic connections — in the frontal cortex of mice within 24 hours. These changes persisted for at least a month. Depression is associated with reduced dendritic spine density in the prefrontal cortex. Psilocybin appears to rebuild what depression has eroded. Patients often describe the experience as a reset — and scans confirm something structural has genuinely changed.

The clinical evidence — what the trials actually show

The clinical evidence has accumulated across multiple independent research groups and continues to strengthen.

Treatment-resistant depression: The COMPASS Pathways Phase 2B trial (n=233, 22 sites, 10 countries) showed a single 25mg dose of psilocybin produced statistically significant improvement over controls at week 3 (p<0.001), with 20.3% sustained response at week 12 versus 10.1% for the near-inactive 1mg control — in patients who had already failed multiple antidepressants. Published in the New England Journal of Medicine, 2022.

Major depressive disorder: Johns Hopkins' randomised clinical trial (Davis et al., JAMA Psychiatry) found rapid, large reductions in depressive symptoms after two psilocybin sessions in adults with MDD, maintained at four-week follow-up. The 12-month follow-up showed 75% response and 58% remission rates. A five-year follow-up published in 2024 showed 67% remained in remission from a single treatment course. Effect sizes are approximately four times larger than those seen with conventional antidepressants.

Head-to-head with SSRIs: Imperial College London's Phase 2 RCT (n=59) compared two 25mg doses of psilocybin against 43 daily doses of escitalopram in moderate-to-severe MDD. Psilocybin performed comparably at the six-week primary endpoint, with favourable trends on secondary emotional and wellbeing measures.

End-of-life anxiety: Two landmark 2016 double-blind RCTs — Johns Hopkins (n=51 cancer patients) and NYU Langone (n=29) — found approximately 80% of participants maintained clinically significant relief from a single dose at six-month follow-up. Approximately 60% achieved full symptom remission.

MDMA for PTSD: The MAPS Phase 3 trials (MAPP1 and MAPP2, Nature Medicine, 2023) showed 67–71% of MDMA-assisted therapy participants no longer met PTSD diagnostic criteria versus 32–48% placebo. Despite these results, the FDA issued a Complete Response Letter in August 2024 declining to approve MDMA therapy. The FDA's concerns were specific: functional unblinding (participants could tell they received MDMA, potentially inflating self-reported outcomes), data integrity concerns, and documented ethical misconduct including a participant who was sexually abused by her therapists in Phase 2 trials. The FDA has requested an additional Phase 3 trial. The underlying science may prove sound, but the regulatory pathway needs to be rebuilt on more solid ethical and methodological ground.

MDMA and Parkinson's — an unexpected window

In the late 1990s, a British stuntman named Tim Lawrence — whose film credits included Braveheart and Frankenstein — was diagnosed with Parkinson's disease at age 34. After years on L-DOPA he developed dyskinesias. While clubbing, he took ecstasy, and within 30 minutes his tremors dramatically reduced. He spent hours performing forward rolls, somersaults, and backflips he could not do sober. BBC Horizon filmed this for their 2001 documentary "Ecstasy and Agony."

It is important to be precise: Parkinson's disease is caused by the death of dopamine-producing neurons in the substantia nigra, producing a resting tremor, rigidity, and slowness of movement. It is distinct from Motor Neurone Disease (which causes progressive muscle weakness and paralysis, not tremor) and from Huntington's disease (which causes jerky choreiform movements). The tremor in that documentary is Parkinson's.

Researchers at the University of Manchester — Professor Alan Crossman and Dr Jonathan Brotchie — called Lawrence's response "the biggest effect we have ever observed in our study of movement disorders" and investigated the mechanism. Brain scans confirmed that MDMA did not increase dopamine production. The benefit was serotonin-mediated: in Parkinson's patients on L-DOPA, surviving serotonergic neurons compensate for dead dopaminergic ones by handling L-DOPA without the autoregulatory feedback of proper dopamine neurons, causing erratic dopamine release that drives both wearing-off and dyskinesias. MDMA's flood of serotonin appears to modulate this system via 5-HT2A receptors. Animal studies in MPTP-lesioned primates confirmed MDMA inhibits dyskinesia and normalises motor activity (Journal of Neuroscience, 2003). R-MDMA specifically reduced peak-dose dyskinesia severity by 33–46%.

MDMA itself cannot be used long-term in Parkinson's — repeated use is neurotoxic and would likely accelerate the disease. It also interacts dangerously with MAO-B inhibitors (selegiline, rasagiline) commonly prescribed for Parkinson's, with serotonin syndrome a serious risk. But the finding points toward a genuine research direction. A safer non-psychoactive MDMA analogue called UWA-101, developed at the University of Western Australia, retains the motor benefits in primate models without psychoactivity or cytotoxicity. Australian biotech Emyria holds exclusive options on UWA-101 and over 100 related compounds. No human clinical trials for Parkinson's have been completed as of 2026. This is a promising lead, not a proven therapy — but it is a lead that deserves formal investigation.

Safety and who it's not for

Psilocybin and MDMA are not for everyone. The trials that produced the impressive results above systematically excluded people with personal or family history of schizophrenia, bipolar I disorder, or other psychotic disorders — because psilocybin can trigger psychotic episodes in predisposed individuals. This is an absolute contraindication. People currently taking lithium face serious interaction risks. SSRIs require a washout period before psilocybin therapy. Patients with uncontrolled hypertension or recent cardiac events are excluded.

The most common adverse events in psilocybin trials are transient: elevated blood pressure, headache, nausea, and anxiety during the session. Hallucinogen Persisting Perception Disorder (HPPD) — persistent visual disturbances after the drug has cleared — affects an estimated 1 in 20 lifetime psychedelic users, with roughly 4% of those affected reporting symptoms severe enough to seek help.

MDMA carries additional risks: dose-dependent serotonergic neurotoxicity at high or repeated doses (though therapeutic regimens appear substantially safer than heavy recreational use), cardiovascular effects, and the heightened emotional vulnerability that makes proper therapist ethics non-negotiable. The FDA's MDMA rejection was partly driven by documented therapist misconduct — a reminder that a drug which creates trust and openness demands practitioners who can be trusted with it.

The safety profile in carefully designed trials is genuinely favourable. The risks outside controlled settings are substantially higher. These are medicines for clinical use with trained professionals — not recreational drugs that happen to also work as therapy.

What NZ patients say

New Zealand patients are not waiting. The NZ Drug Foundation's data shows psychedelic use doubled in six years. A 2025 academic study documented widespread self-treatment with psychedelic substances for health and wellbeing in Aotearoa, with nearly half of self-treaters having previously tried conventional pharmaceuticals and found them inadequate. Underground facilitated retreats are operating across New Zealand, run by guides without medical training who cannot manage psychiatric emergencies and cannot verify what they are administering.

Alice Brent, Christchurch, was New Zealand's first legal psilocybin patient when she received treatment in October 2025. She had tried everything else. After her session, she told 1News: "I felt big emotions to my core." She said she wanted to see weddings and grandchildren. Until the treatment, she had not wanted to see anything.

The demand is real, the evidence is compelling, and the underground is already operating. The question for New Zealand is not whether these therapies will be used — they already are. The question is whether they will be used safely, equitably, and with proper clinical oversight. That requires building a system, not approving a single prescriber and hoping the problem takes care of itself.