Psychostimulants and energy drinks: Are they a risky combination?

Psychostimulants are medications prescribed to treat attention deficit hyperactivity disorder (ADHD), with or without hyperactivity. They are used by children, adolescents and adults alike. In Québec, prescriptions for psychostimulants are issued at nearly twice the rate seen in other Canadian provinces.

Like many medications, psychostimulants can interact with other substances. One of the most common is caffeine, a key ingredient in energy drinks, which are especially popular among young people. Let’s take a closer look at why combining the two may pose a risk.

What are psychostimulants?

Psychostimulants mainly fall into two categories:

• Amphetamine-based medications
• Methylphenidate-based medications

They work by increasing the levels of two chemical messengers in the brain: dopamine and norepinephrine. These substances play a key role in attention, impulse control, mood regulation and behaviour.

Thanks to these effects, psychostimulants help people with ADHD improve focus and reduce impulsivity. When prescribed by a healthcare professional and taken under proper medical supervision, these treatments are considered both effective and safe.

Possible effects on the heart

Because psychostimulants are, by nature, stimulating substances, they can affect the cardiovascular system. In some individuals, they may:

• Increase heart rate
• Raise blood pressure
• Cause heart palpitations

These effects are generally monitored during regular medical follow-ups.

What’s in energy drinks?

Energy drinks are popular beverages that mainly contain caffeine and sugar. They also often include other ingredients, such as taurine and B vitamins, which can enhance their stimulating effect.

Caffeine stimulates the nervous system. In higher amounts, it can increase heart rate and trigger palpitations.

These drinks are particularly appealing to young people, often marketed as a way to boost concentration or athletic performance. In 2020–2021, about one in five Quebecers aged 15 to 24 reported consuming at least one energy drink per week.

How much caffeine is considered safe?

Current recommendations suggest not exceeding:

• 400 mg of caffeine per day for adults aged 18 and over (excluding pregnant or breastfeeding women)  
• 2.5 mg of caffeine per kilogram of body weight for those under 18

A single energy drink can contain anywhere from 80 mg to 180 mg of caffeine. It’s therefore easy to exceed recommended limits, especially when multiple drinks are consumed in the same day. Some people are also more sensitive to caffeine and may experience unwanted effects even at lower doses.

Why do energy drinks increase the risk?

Several factors make energy drinks particularly concerning. They are often sweet, served cold and easy to drink quickly, unlike a hot coffee that is consumed more slowly. Their use is also sometimes normalized among young people.

In addition, some consumers are not fully aware of their ingredients or the risks involved, especially when energy drinks are combined with other stimulating substances. Because they are widely available, these drinks are often used to enhance academic or sports performance, or simply to fit in socially.

A dangerous combination

ADHD medications and energy drinks share one important characteristic: they both stimulate the heart. When taken together, their effects may amplify each other rather than simply add up.

Although the cardiovascular risk associated with psychostimulants remains relatively low, it is real. For this reason, combining them with other stimulants such as caffeine is generally not recommended. Even seemingly moderate amounts can lead to significant side effects.

The importance of prevention and awareness

In response to these risks, some countries have already banned the sale of energy drinks to young people under 16 or 18 years of age. In Québec and elsewhere, efforts are ongoing to strengthen regulations and improve warning labels.

Better education for young people, parents and professionals is essential to help prevent serious consequences. Raising awareness about drug interactions and safe caffeine consumption remains an important public health issue.

If you’re unsure or have concerns, don’t hesitate to talk it through with a healthcare professional.