Anxiety claims and evidence

Anxiety is one of the most common reasons people ask about medicinal cannabis in New Zealand, yet it is also one of the most poorly supported by high-grade research. The evidence for cannabis preparations in anxiety is still early-stage, mixed, and heavily influenced by cannabinoid profile, dose, and the individual’s prior experience with THC. This page separates the established evidence from the uncertain evidence and from marketing claims, so you can have a realistic conversation with a prescriber.

What the evidence actually shows

The strongest clinical signal for cannabis in anxiety is for CBD (cannabidiol), not THC. A 2020 systematic review in Frontiers in Psychiatry found that CBD reduced anxiety in several small experimental studies, but the authors noted that most trials were short, used healthy volunteers rather than patients with diagnosed anxiety disorders, and used doses that are higher than what is typically prescribed in New Zealand. The review concluded that CBD shows “potential” but is not yet an established first-line treatment.

A 2019 review in The Lancet Psychiatry examined cannabinoids for psychiatric disorders and found no high-quality evidence that either CBD or THC improves anxiety disorders. The authors noted that most studies were small, short, and industry-funded, and that the few trials showing benefit for social anxiety used single doses of CBD (300-600 mg) under laboratory conditions, not repeated treatment in real-world patients.

A 2017 systematic review by the US National Academies of Sciences, Engineering, and Medicine found “substantial evidence” that cannabis preparations are effective for chronic pain, and “moderate evidence” for use as an anti-emetic; for anxiety, the evidence was described as limited or preliminary. The review also noted that CBD-predominant options show some promise in early-phase trials for social anxiety, but the overall evidence base was insufficient to recommend cannabis for anxiety as a first-line treatment.

A 2023 systematic review of 12 randomised controlled trials (RCTs) found that CBD-dominant preparations reduced anxiety symptoms in some social anxiety and generalised anxiety trials, but effect sizes were modest and many trials had small samples. The same review noted that THC-dominant preparations had inconsistent results; some patients reported increased anxiety at higher THC doses. A 2023 systematic review in the New Zealand Medical Journal (NZMJ) found that CBD-dominant options showed moderate effect in social anxiety models but inconsistent results in generalised anxiety disorder; the review emphasised that most trials used synthetic cannabinoids, not plant-derived material, and that no preparation available in New Zealand has been approved for anxiety specifically.

What the prescribing guides say

The NZ Formulary, which guides prescribers in New Zealand, does not list anxiety as an approved indication for medicinal cannabis. The prescribing guide notes that evidence for anxiety is limited and that CBD is the primary cannabinoid studied, with THC more likely to worsen anxiety at high doses. Healthify (Health Navigator) notes that while some patients report reduced anxiety with CBD, evidence is inconsistent and more robust for chronic pain, spasticity, and chemotherapy-induced nausea. Prescribers must make an individual clinical judgement, and the decision is based on the prescriber’s assessment of potential benefit versus harm, not on a formal registered indication.

How the Medicinal Cannabis Scheme works

The New Zealand Medicinal Cannabis Scheme was established under the Misuse of Drugs (Medicinal Cannabis) Amendment Act 2018, with the scheme operational from1 April2020. The scheme does not create a general right to possess or use cannabis; the only legal route is via a prescription from a medical practitioner and a preparation that meets the quality standard.

The scheme is administered by the Medicinal Cannabis Agency (MCA), which sits within Medsafe. Medsafe approves preparations under the scheme, and the MCA issues licences. The Ministry of Health states that the scheme’s purpose is to facilitate access to quality medicinal cannabis while ensuring appropriate safeguards. Prescriptions are issued under the Misuse of Drugs (Medicinal Cannabis) Regulations2019.

Preparation categories and legal status

Preparations are divided into two categories under the scheme:

• CBD preparations containing mostly CBD, with no more than2% THC. These are not controlled drugs and can be prescribed by any doctor.
• THC preparations containing more than2% THC. These are controlled drugs requiring a controlled drug licence for prescribing and are more strictly regulated.

Further classification by cannabinoid ratio includes:

• CBD-dominant: more CBD than THC
• THC-dominant: more THC than CBD
• Balanced: roughly equal THC and CBD

The legal maximum daily dose for CBD is60 mg/day under the Misuse of Drugs Regulations; anything above is a controlled drug. THC preparations are controlled drugs regardless of dose. CBD itself is non-psychoactive and not controlled under the Misuse of Drugs Act, but the CBD preparation still needs to be a ministry-approved medicine and prescribed.

What forms are available

Preparations come as flower, oils, capsules, and oral sprays. “Full spectrum” refers to material containing multiple cannabinoids and terpenes; “isolate” refers to purified single-molecule material (e.g., CBD isolate). Examples by THC:CBD ratio include high-THC (e.g., Tilray25:25), balanced (e.g., Medleaf THC10:CBD10), and high-CBD (e.g., CBD100). Raw flower, while available, is prescribed and dispensed through a pharmacy, not a dispensary. Smoking raw plant material is not permitted under the scheme; prescribed flower is intended for vaporisation, not combustion. Vapour is the only inhaled method explicitly accommodated.

The patient pathway

1. Consult a doctor.
2. The doctor assesses eligibility. Most GPs can prescribe, but many choose to refer to specialists. Some GPs are authorised to prescribe without specialist referral; others use Schedule1 approval.
3. The doctor issues a prescription. A medical practitioner may prescribe a medicinal cannabis preparation if they consider it clinically appropriate, and the preparation must meet GMP standards and be approved by the ministry. Prescribers do not need special registration but must follow the NZ Formulary.
4. A licensed pharmacy dispenses a GMP-certified preparation. There are no dispensaries.
5. Attend follow-up reviews. Clinical guidance from the NZ Formulary and Healthify emphasises starting low and going slow, with regular review.

Preparations must be GMP-certified and approved by the MCA before they can be prescribed. The NZ Formulary lists cannabis monographs and provides dosing guidance for clinicians; it is a prescribing guide, not an approval list. Prescribers may also prescribe unapproved preparations that meet the requirements of Section29 of the Misuse of Drugs Act. The average cost is NZD5-15 per day for flower and NZD3-10 per day for oil, but this is an estimate from the Medicinal Cannabis Agency’s2023 annual report and varies widely.

Risks, side effects and cautions

Driving

New Zealand law prohibits driving with any detectable THC in oral fluid. Even if you feel fine, you may test positive for hours or days after use. This is an urgent safety boundary: do not drive after using any THC-containing preparation.

Common side effects

Dry mouth, drowsiness, dizziness, increased appetite, and changes in blood pressure are common. THC can cause anxiety or paranoia, especially at higher doses or in THC-naive patients. CBD is generally well tolerated but can interact with warfarin and other CYP-metabolised drugs. Tell your prescriber about all other medicines you take.

Contraindications

Do not use medicinal cannabis if you are pregnant, breastfeeding, have unstable psychiatric conditions, or have severe liver disease. These are absolute boundaries under current clinical guidance.

Distinctive claim

No medicinal cannabis preparation available in New Zealand has been approved specifically for anxiety, and the NZ Formulary does not list anxiety as an approved indication; every prescription for anxiety is an off-label clinical judgement made by an individual doctor after standard treatments have failed.