Published on March 12th, 2012 | by James Johnson0
Large Doses Of ADHD Drugs Could Harm Learning [Study]
Researchers examining the effects of ADHD drugs on monkeys have discovered that the drug methylphenidate interfered with learning development and memory when given in high doses.
In 1977 a study found that law doses of the drug helped children perform better when dealing with ADHD, however the new study finds that high doses impair learning responses.
According to Luis Populin, an associate professor of neuroscience at the University of Wisconsin-Madison School of Medicine and Public Health:
“Many people were intrigued by that result [1977 study], but their attempts to repeat the study did not yield clear-cut results.”
The new study is available now in the Journal of Cognitive Neuroscience (published last week).
In the study three monkeys were taught to focus on a central dot on a screen while a “target” dot flashed nearby. If they waited until the central dot was turned off and then looked at the spot where the dot had been they were taught that they would receive a sip of water.
According to ScienceDaily:
The system tests working (short-term) memory, impulsiveness and willingness to stick with the task, as the monkeys could quit “working” at any time, says Populin. The study used different doses of methylphenidate — the generic name for Ritalin — that were comparable to the range of clinical prescriptions for ADHD.
Researchers found much like the 1977 study that low doses improved performance scores because impulses were controlled, allowing the monkeys to wait long enough to focus their eyes on the target. At higher doses however all three monkeys continued making the same errors repeatedly. Interestingly enough the monkeys stayed on task twice as long under higher doses of the ADHD drug but they had a harder time performing the task.
The study is important because the Centers for Disease Control and Prevention (CDC) estimate that 5% of children in the United States are now taking ADHD based drugs.
According to researchers methylphenidate affects the brain’s executive function:
“Which can create an internal environment that, depending on the dose, is either more or less amenable to memory formation and/or retention. If you can concentrate, and are able to process information without being interrupted by distracting thoughts or distractions in your environment, you will perform much better on a memory test. Apparently, the lower dose of methylphenidate helped create the conditions for success without actually improving memory itself.”
The next step for researchers will be to test the findings on human participants which they suspect will react in the same way.
Does it surprise you to learn that over medicating of ADHD drugs can negatively affect learning and memory?