ADHD and Cannabis: What the Evidence Says

Many Australians with ADHD — diagnosed or suspected — use cannabis to manage restlessness, focus or sleep. But the current evidence doesn't support cannabis as a treatment for ADHD, and combining it with stimulant medication carries real risks. In fact, both are Schedule 8 controlled medicines, and most Australian doctors won't prescribe them together.

This article explains how each substance affects the brain, why the combination is considered unsafe, and what to do if you're concerned about ADHD or your current treatment.

Impact of Stimulants

Stimulant medications increase the production of dopamine and other neurotransmitters in the brain. The outcome of these increased chemicals improves focus, memory, motivation, and thinking speed. More information can be found here.

Impact of THC:

THC (the active ingredient in cannabis) activates cannabinoid receptors and increases dopamine too, causing the “high” feeling.

THC can also disrupt memory, reduce motivation, and impair thinking and decision-making. A report by Harvard Medical School outlines the effects of THC on the brain and body.

The Problem

When both medications are taken together the potential of negative implications may develop including,

• Severe anxiety or panic attacks
• Paranoia or psychotic symptoms (hallucinations, delusions)
• Poor judgment and risky behaviour
• Addiction potential
• Uncontrollable mood swings

The brain’s dopamine system can handle one psychoactive medication, but two at the same time creates unpredictable and dangerous effects.

Stimulants and Your Heart

Stimulant medications increase:

• Heart  rate and blood pressure, often raising your normal heart rate and resting heart rate
• Your body’s stress response
• The effort required to keep blood flowing to your organs, which increases workload on the heart muscle

For most healthy people, this is safe in the short term. Your heart can handle these changes when you’re only taking one medication.

Cannabis and Your Heart

It can cause:

• Increased heart rate
• Dizziness when standing up
• High blood pressure
• Increased heart strain and changes in blood flowing through the coronary arteries

Regular cannabis use in people with existing cardiac risk factors or a known heart condition can increase the risk of heart attack or cardiac arrest, especially when combined with stimulant medications.

When You Take Both Together

Higher strain is placed on the heart leading to:

• Heart palpitations (feeling your heart skip or race)
• Dangerous blood pressure spikes and abnormal heart rate and blood pressure patterns
• Irregular heartbeats, including atrial fibrillation in people with structural heart disease
• Fainting
• Chest pain
• In rare cases, heart attack and life-threatening cardiac arrest

People at highest risk include those with:

• Existing heart conditions such as coronary heart disease, atrial fibrillation, or other structural heart disease
• Anxiety disorders
• High  baseline or elevated resting heart rate
• Family history of heart problems or premature heart attack

Major organisations, including the National Heart Foundation of Australia and leading cardiology groups in the United States, highlight stimulant medications, cannabis use, and other cardiac risk factors as important issues to discuss with anyone who has a heart condition or is at increased risk of heart attack.

Your thinking Gets Worse, Not Better

One of the biggest problems with combining these medications is that cannabis can prevent the effectiveness of stimulant medications.

Cannabis Cancels Out Stimulant Benefits

Stimulants are prescribed to improve:

• Attention and focus
• Working memory
• Processing speed
• Executive function (planning and organization)

If you’re taking a stimulant for better focus and then use cannabis, you are offsetting the positive effects of the stimulant. Additionally this article provides more information on the use of Medical THC in ADHD populations.

Greater Likelihood of further problems

Combined use also increases psychiatric problems:

• Mood instability/ irritability
• Paranoia and suspicion
• Anxiety and panic
• Feeling disconnected from reality
• Psychosis (seeing or hearing things that aren’t there)

Wondering if it’s ADHD?

If you’re using cannabis to manage focus, restlessness or sleep, it’s worth finding out what’s actually going on. Dokotela’s psychiatrists consult via telehealth Australia-wide — you’ll need a referral from your GP, and we can guide you through the rest.

How it works →

What the Law Says in Australia

Both stimulants and medicinal cannabis are Schedule 8 (S8)controlled medicines. This means they have strict rules around prescribing and monitoring.

Why This Matters

When a doctor prescribes both S8 drugs together, it triggers:

• Automatic flagging and prescription monitoring systems
• Increased government oversight and audits
• Requirement to document why both drugs are necessary
• Extra scrutiny from health departments

Legal Responsibility for Doctors

If a patient experiences problems while on both medications—such as psychosis, heart problems, or dangerous driving—the doctor can be held legally responsible.

In practice, most Australian doctors consider it impossible to justify co-prescribing these medications because the risks are well-known and documented.

Clear Clinic Policies

Dokotela will only allow suitable patients to be prescribed stimulants when medicinal THC is not present within a patient’s treatment plan.

This approach protects patients by:

• Maximising the likelihood that stimulants are an effective treatment
• Reducing heart and mental health risks
• Avoiding dangerous drug interactions
• Keeping your care within legal guidelines

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The Bottom Line

Don’t mix stimulants and medicinal cannabis.

Both treatments have real benefits when used alone. Stimulants are effective  for ADHD. Cannabis can help with certain conditions like Tourette syndrome or severe behavioural problems.

Where to Get Help

For more information:

• Talk to your GP or psychiatrist about your treatment options
• Ask your clinic about their prescribing policies
• Contact Beyond Blue or Headspace if you have concerns about medications or mental health

Get a proper assessment

ADHD is best diagnosed and managed by a psychiatrist. Dokotela offers telehealth psychiatry across Australia. Talk to your GP about a referral, or read about getting started below.

Getting started with Dokotela →

Our fees →

Frequently Asked Questions

Does cannabis help ADHD?

Current evidence doesn't support cannabis as a treatment for ADHD. Some people feel it eases restlessness in the short term, but research links regular use to worse attention, memory and motivation — the very things ADHD treatment aims to improve.

Is it safe to use cannabis alongside stimulant medication?

No. Both are Schedule 8 controlled medicines, and using them together increases risks to your heart and mental health. Most Australian doctors will not prescribe both, and Dokotela's policy is not to prescribe stimulants where medicinal THC is part of a patient's treatment plan.

Can I get assessed for ADHD via telehealth?

Yes. Dokotela's psychiatrists conduct ADHD assessments via telehealth anywhere in Australia. You'll need a referral from your GP — see how it works.

What if I'm using cannabis to cope with focus or sleep problems?

Talk honestly with your GP. They can help you work out what's driving the symptoms, and refer you to a psychiatrist for assessment if ADHD or another condition might be involved.

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Further Information

RACGP medicinal cannabis safety guide

https://www1.racgp.org.au/ajgp/2021/june/a-primer-on-medicinal-cannabis-safety-and-potentia

AHA cannabis cardiovascular warning

https://www.ahajournals.org/doi/10.1161/CIR.0000000000000883

UK cannabis ADHD registry data

https://onlinelibrary.wiley.com/doi/10.1002/npr2.12400

If you or someone you know is struggling, support is available 24/7 — call Lifeline on 13 11 14.