A recent Australian study has managed to reveal a "significant lack of effect" of some of the most commonly used medicines to treat ADHD, and this has become a finding which has surprised many experts, including one of the researchers involved.

Co-author of the WA-based research, which analyzed the effectiveness of drugs now used almost everywhere to treat Attention Deficit Hyperactivity Disorder in kids, Professor Lou Landau has been much shocked by the revelations of the study.

The Chief Medical Adviser to the West Australian Department of Health stressed that he was not expecting such a strongly negative result.

"Yes, we weren't anticipating that significant effect... or the significant lack of effect of the medication", he said.

For the sake of study, researchers’ analyzed data collected from the country's long-term Raine Study to assess the health, and other, outcomes of 131 children with ADHD, in over 2,800 Australian families. It revealed how those on traditional ADHD drugs, like as Ritalin and dexamphetamine, displayed poorer educational outcomes, than children with ADHD not on the medicines.

The WA Government released the report on Wednesday.