EDITORIAL Methylphenidate-Induced Neuropathology in the Developing Rat Brain: Implications for Humans

Imagine the following experiment. Researchers administer a certain drug to young rats, and subsequently find that the drug has harmful long-term effects. This straightforward experiment has been done numerous times with numerous drugs. It is common for the researchers, in their published papers, to at least make some suggestions about what the findings in rats might mean for human brain development. If the drug in question is illicit, the results are usually held up as one more reason to refrain from using the drug. If the drug happens to be a prescription drug, most scientists would at least suggest the need for increased caution by the medical profession—especially if the drug’s target market is young children. Interestingly, the above experiment was recently conducted with a common drug given to millions of children. The study was done by William Carlezon and his colleagues at Harvard Medical School (Carlezon, Mague, & Anderson, 2003). The drug in question? Ritalin. And, indeed, the researchers discovered that Ritalin has harmful long-term effects on the developing rat brain. In their study, young rats exposed to Ritalin had an increased risk for depression later in adulthood.1 You would think that this would at least suggest that children diagnosed with attention deficit hyperactivity disorder (ADHD) and given Ritalin might be at risk; however, this straightforward conclusion poses a significant public relations problem for the people responsible for the rapid increase in the use of Ritalin in this country. But, given their astute public relations skills and the inability of the press to critically analyze scientific reports, the obvious conclusion had little chance of making the news. Instead, a flawed series of illogical steps in thinking resulted in the media reporting that the main message of the study is that children need an accurate diagnosis of ADHD. How did this happen? Let’s start with the American College of Neuropsychopharmacology’s (ACNP) press release about the study (Lobliner, 2004). Amazingly, the press release concluded that the study only has implications for “normal” children and not for children diagnosed with ADHD. In fact, not only does the ACNP forgo the slightest suggestion that Ritalin might be harmful for “ADHD” children, it goes out of its way to explain that the results do not apply to “ADHD” children. According to their logic, only if you have an incorrect diagnosis of “ADHD” will Ritalin be harmful. It is interesting to examine how a press release takes data, showing that Ritalin harms the brains of rats, and then turns that data into the message that Ritalin will only harm children with an incorrect diagnosis.2 The major flaw in their logic starts with the explanation that the rats in the study were not “ADHD” rats but “normal” rats. Labeling the rats as normal allows the ACNP to assert that the findings only have implications for normal children. The ACNP has basically Ethical Human Psychology and Psychiatry, Volume 7, Number 2, Summer 2005