A report in the February 23 issue of the Journal of the American Medical Association (JAMA) describes a disturbing trend in the rate at which the stimulant Ritalin is prescribed for preschool-aged children.

Dr. Julie Mango Zito and her colleagues at the University of Maryland and Johns Hopkins University found that between the years of 1991 to 1995, prescriptions of Ritalin for children aged three years and younger increased two to three fold. The researchers examined the prescription records of two Medicaid programs-one in a Midwest state and the other in a mid-Atlantic state-as well as the records of an HMO in the Northwest to determine their findings.

Ritalin is a mild stimulant that is often prescribed to treat Attention Deficit Hyperactivity Disorder (ADHD). Although the list of possible signs of ADHD is long, the three hallmark symptoms are: difficulty paying attention, impulsive talking and behavior, and hyperactivity that often manifests as excessive fidgeting and squirming. Ritalin is thought to relieve the symptoms of ADHD by allowing the brain to ignore distracting stimuli.

The increase in the prescription rate of Ritalin was sharp enough to generate a great deal of attention in the media. The study also prompted First Lady Hillary Clinton to announce a federally funded $5 million research project that will investigate issues involving psychiatric drugs for children, including a study of children who take Ritalin to treat attention-deficit disorder.

One disturbing aspect of the increase in Ritalin use by preschoolers is that Ritalin is not officially endorsed for treatment of children under the age of 6. The package insert reads “Ritalin should not be used in children under 6 years, since safety and efficacy in this age group have not been established.” While there is no definitive evidence that Ritalin use in children younger than 6 will cause harm, a 1998 report in the Journal of Child and Adolescent Child Psychopharmacology found that preschool age children suffered from the adverse side effects of Ritalin more strongly than did the older children.

Studies of brain development have shown that the period between birth and age 4 is a time of extensive growth and change in the brain. Since the long-term effects of Ritalin on brain development are not known, many experts urge extreme caution when using it in very young children.

Part of the controversy over Ritalin involves the existence of ADHD itself. Although the US Surgeon General and the US Agency for Health Care Policy Research both reported last year that the standard diagnosis for ADHD contained in the mental health manual DSM-IV is acceptable, many psychologists have publicly stated that attention-deficit disorder is not a true illness. Diane McGuinness, a psychologist and author of “When Children Don’t Learn,” was quoted in the Seattle Times: “methodologically rigorous research indicates that attention deficit disorder and hyperactivity as ‘syndromes’ simply do not exist. We have invented a disease, given it a medical solution, and now must disown it.” Other psychologists suggest that while the disorder exists, it may be over-diagnosed. Dr. David Kupfer, professor of psychiatry at the University of Pittsburgh School of Medicine, told Business Week that “There is no consistency in treatment, diagnosis, or follow-up for children with ADHD.”

Two current studies offer hope of a consistent clinical test for attention-deficit disorder. Psychiatrists at McLean Hospital in Belmont, Massachusetts are using an infrared tracking device to detect subtle movements of children as they fulfill a number of attention tests. The researchers used the results from the device and the scores on the attention test to determine whether each child had ADHD. The group also scanned the brains of these children, and they found that the children who performed most poorly on the attention tests also had lowered activity in an area of the brain called the putamen. The researchers found that when six of the confirmed ADHD boys were given Ritalin, they showed improved activity in the putamen as well as improved scores on the attention tests. However, children who did not meet the diagnostic test for ADHD actually showed less activity in the putamen and no improvement on the test when they were given Ritalin. These results suggest that a misdiagnosis of ADHD, and the consequent wrongful prescription of Ritalin, could cause harm to children who do not actually have the disorder.

Boston Life Sciences Inc., a small biotech startup in Boston, is developing a second test for ADHD. They have developed an agent called Altropane, which binds to brain cells that create dopamine. Many researchers believe that ADHD is caused by a genetically induced imbalance in the brain chemical dopamine. Boston Life Sciences hopes to use a combination of Altropane and brain scanning techniques to correlate the levels of dopamine to the symptoms of ADHD. Their preliminary results suggest that adults with an established history of ADHD have higher levels of dopamine producing neurons than non-ADHD adults of the same age. If applicable to children, this test could allow doctors to more accurately diagnose attention-deficit disorder and tailor treatment for each individual’s dopamine levels.

The use of Ritalin in very young children is controversial, primarily because there is so little information on the potential harm it could cause to a developing brain. Until further studies are done and more accurate diagnoses of ADHD can be made, it may be wise to exercise some caution before allowing preschool aged children to enter the ranks of the chemically assisted.