What’s the link between ADHD medication and psychosis?

This year, several alarming reports have warned that Australians are developing psychosis from using stimulant medications, typically prescribed for attention deficit hyperactivity disorder, or ADHD.

Psychosis itself is not a diagnosis; it’s a mental health symptom that involves having difficulty separating what is real from what is not. People might hear, see, feel, taste or smell things that don’t exist, or they can start to develop ideas that don’t reflect reality.

For some people (an estimated one in 200 Australians ) psychosis is part of a mental illness, such as schizophrenia. Others will experience a psychotic episode once and fully recover.

While psychosis is uncommon, it is a serious health issue that can require acute care.

So, with an increasing number of Australians taking ADHD medication , how worried should we be?

First, what medications are we talking about?

In Australia, stimulants are the most common drug prescribed for ADHD. The main types include methylphenidate (brands such as Ritalin and Concerta) and members of the amphetamine family, dexamfetamine and lisdexamfetamine (sold as Vyvanse).

Non-stimulants – such as atomoxetine, and guanfacine and clonidine – are also prescribed, but are less common.

Stimulants work by boosting dopamine and noradrenaline. These are neurotransmitters that are important for reward, motivation and focus. Imagine having 50 browser tabs open at once. Stimulants can help minimise the background tabs, so people can focus on the main screen.

Increased awareness of ADHD means diagnosis rates have also increased – and so has the number of people prescribed stimulant medicines.

In 2004-05, two in every 1,000 Australians were dispensed a government-subsidised ADHD medicine. By 2023-24 it was 22 in 1,000, or just under 600,000 people .

Stimulant medications made up 87% of ADHD prescriptions in 2023-24, which is not surprising given they are a first line evidence-based treatment recommended for ADHD.

Evidence shows stimulants are helpful

There is strong data to support the effectiveness of these medicines for improving ADHD symptoms. Reviews combining the results of more than 100 trials have found that using stimulants is linked to significantly reduced ADHD symptoms such as impulsiveness and distractibility.

There are other significant benefits. ADHD stimulant use is linked to reduced risk of motor vehicle accidents, substance misuse, suicidal thoughts and behaviours, and criminal convictions .

So, what’s the risk of psychosis?

The possible increased risk of psychosis when taking these stimulant medications is similar, and perhaps even lower, compared to other widely used medications, such as oral glucocorticoids , used to treat asthma flare-ups.

When people are properly assessed and their treatment is monitored, rates of psychosis induced by stimulants is low (0.2-3% of this population). This is lower than the prevalence of many psychotic disorders in the general population.

For example, one US study of more than 220,000 teenagers and young adults starting stimulant medicines found that about one in 660 developed psychosis in the months after starting medication.

Research that combined 16 different studies across 390,000 people with ADHD found a low overall risk of psychosis: 2.8% of people prescribed stimulants developed psychotic symptoms. This does not mean they developed a lasting disorder – and there is less evidence of a link to this serious issue.

But the risk of harm – including psychosis – is likely higher when these medications are used without a prescription , or drugs are illicit . Non-therapeutic use can involve taking high doses of methamphetamine or other stimulants, often smoked or injected.

We need to put the evidence in context

First, some studies show no link at all between stimulants and psychosis, suggesting the evidence about risk is still developing. A recent Finnish study of nearly 4,000 young people prescribed methylphenidate (Ritalin or Concerta) found no relationship between using the drug and an increased risk of psychosis.

Second, there is some evidence to suggest people with ADHD may have a higher risk of psychosis, whether or not they use medication . So where studies have found a relationship between ADHD medication and psychosis, it could be due to pre-existing factors, not the medication itself.

Third, while the overall risk remains low, there are some differences between different types of stimulants. For example, in two population-based studies , psychosis was about twice as common with amphetamines as with methylphenidate .

So, what should people taking ADHD medications know?

1. Don’t rely on brief online assessments

If you require assessment and support for ADHD, including medications, make sure your practitioner provides an evidence-based assessment . Online assessments that are brief and rely on only on questionnaires are not enough .

Proper assessment will typically involve your health-care practitioner taking a thorough developmental history, asking enough questions to rule out other mental health concerns, and obtaining reports from other people who know you to inform their decisions. To understand your individual risk and tailor treatment, they will typically need to see you over multiple sessions.

2. Take your medication as prescribed

Always follow your prescription and don’t make any dose changes without discussing with your doctor first.

3. Keep monitoring for any changes

Check in regularly with your doctor and other health-care professionals. They will be able to monitor any potential warning signs and change your treatment plan if needed.

Are ADHD medications safe?

ADHD medications are among the most studied medicines in psychiatry and have been shown to reduce serious harms linked to ADHD. But people taking ADHD medications still need to know information about the potential risks, and what to watch for.

Always take your medication as prescribed, don’t use someone else’s medication, and if you have any concerns, speak to your health-care professional.