New study: Adhd medicine affects brain development

Methylphenidate is the active substance in, for example, Ritalin and Concerta, two medications prescribed to thousands of Swedish children and adolescents for the treatment of ADHD.

But if and if so, how this medication affects the brain in the long run, nobody knows.

- In previous studies, attempts have been made to statistically control the effects of this medication. This is the first study in which we investigate untreated patients, which - of course - is absolutely crucial to find out how the medication affects a developing brain, says one of the authors of the current study, Liesbeth Reneman at the University of Amsterdam, the journal Radiology where the study is published.

To find out more, Reneman and her colleagues recruited 50 boys and 49 young adults with diagnosed ADHD, but who had not yet begun to take methylphenidate.

Patients were then given either methylphenidate or ineffective placebo for 16 weeks, while their brains were examined with a magnetic camera at the beginning and end of the study period.

Using the DTI (diffusion tensor imaging) technique, the white matter of the brain was examined, that is, the part of the brain that lies within the cerebral cortex and which manages the communication between the cerebral cortex's nerve cells.

After four months, there were clear changes in the white matter regarding these parameters in medicated boys, but not in adult adults.

- The results show that adhd medication can have different effects on the structure of a developing brain. However, in adult men with ADHD and in both men and boys who received a placebo, these changes did not appear, suggesting that the effect of methylphenidate on the white matter of the brain is dependent on the patients' age, says Reneman.

If and if so, what effect these changes have on patients in the longer term, the researchers do not yet know, but they conclude that the regulation which receives this type of medication should be tougher.

- The use of ADHD drugs in children must be carefully considered until we know more about the long-term effects, says Reneman.

Karl Mikael Kälkner at the Swedish Medicines Agency says it is too early to say whether the changes that the study sees are a problem.

- Just because you see a change you can't tell if it's good or bad.

- It may be an expected treatment effect you have seen, he continues.

He also believes that one is already restrictive in giving adhd medication.

- The recommendations are that you should have tried non-pharmacological treatments first, from a structured environment, that you move and that you have breaks in your learning, says Karl Mikael Kälkner.

But the number of children and adolescents receiving ADHD has increased significantly in recent years. In 2006, almost 10,000 children aged 0-19 received treatment with central stimulants, in 2018 the figure was just over 50,000.

In terms of the number of patients per 1,000 inhabitants in the same age group, the number has increased from 4.44 patients in 2006 to 21.57 patients in 2018, according to figures from the National Board of Health and Welfare.

- Although the increase may seem dramatic, the levels today are quite reasonable, says Peter Salmi at the National Board of Health and Welfare.

- There has been a greater general awareness of adhd and it has gone fast. It is this development that has led to the rapid increase. It is not that adhd has increased in society, it is considered constant. It is a dark figure now emerging, he says.