More threads by David Baxter PhD

David Baxter PhD

Late Founder
Studies linking Ritalin and depression highlight risk of overdiagnosing ADHD
January 25, 2005
Associated Press

New research is raising questions about the long-term effects of Ritalin and other drugs widely used to treat attention-deficit hyperactivity disorder.

While most people agree that Ritalin and similar drugs can dramatically improve the lives of kids suffering from ADHD, doctors and parents have long been concerned about how the drugs might affect a child's developing brain. Now, new studies in rats suggest that methylphenidate, the generic name for Ritalin, may permanently alter the brain and may lead to depression in adulthood.

While the studies have limits - a rat's brain is obviously very different than a child's - the research nonetheless highlights the need to be sure of an ADHD diagnosis before putting a child on medication. ADHD has been estimated to affect 3 percent to 12 percent of children and is twice as common among boys as in girls. But the criteria for the disorder - such as whether a child is easily distracted, doesn't seem to listen or can't sit still - are highly subjective and could easily describe many healthy children. Some psychiatrists believe that as many as 15 percent of kids diagnosed with ADHD actually suffer from some other problem that wouldn't be helped by drugs - such as a learning disability, a sleep disorder or even a difficult relationship with a teacher.

Efforts are increasing to make ADHD diagnoses less subjective. Now, "many kids are put on Ritalin when there's very weak evidence," says Eric Nestler, chairman of the psychiatry department at the University of Texas-Southwestern Medical Center in Dallas.

This latest research has particular significance for healthy children who have been wrongly diagnosed and put on ADHD medication. In December at the annual meeting of the American College of Neuropsychopharmacology, researchers from Harvard Medical School's McLean Hospital in Belmont, Mass., presented a study on depressive symptoms that developed in adult rats exposed to Ritalin early in life. Researchers at the University of Texas-Southwestern in Dallas have reported similar findings.

While a rat study certainly can't be the final word on the risks or benefits of any drug, the animals are a particularly valuable proxy to monitor drug effects in a young brain, because for ethical reasons it's difficult to study children.

In both rat studies, young rats were exposed daily to Ritalin or a placebo, using doses that mimicked Ritalin use in childhood. The treatment was stopped for a period of time, and adult rats were tested for signs of depression and despair. The researchers found that rats exposed to Ritalin were less interested in sugar water and sexual activity than their counterparts who had never been given the drugs.

And in stressful situations, Ritalin rats gave up on tasks more quickly. In a Harvard test, the rats were left to swim in a tank. The Ritalin rats gave up and floated after about three minutes, nearly two minutes sooner than other rats.

Notably, the rats were also exposed to cocaine. The Ritalin rats were far less interested in the drug than other rats. That suggests kids exposed to Ritalin probably aren't at higher risk for abusing drugs. But it may also indicate that brain pathways involved in pleasure and aversion, which can subsequently influence behavior, have been changed, increasing the risk for depression.

The research measures only the impact of Ritalin on a healthy rat brain. As a result, the studies are best extrapolated to healthy kids, and emphasize the importance of getting the right diagnosis before putting a child on Ritalin. While only Ritalin was studied, scientists say it's reasonable that other stimulants used to treat ADHD, such as Concerta or Adderall, would likely show similar effects.

"In defense of parents, they figure giving Ritalin is like giving aspirin," says William Carlezon, a Harvard associate professor of psychiatry and co-author of the most recent study. But "one of the important implications of our work is that the effect of Ritalin doesn't go away."

ADHD can be difficult to diagnose, and doctors rely on reports from teachers and parents to determine how disruptive the problems really are. But such methods are notoriously unreliable. In one recent McLean study, data collected from 1,000 children showed some teachers never rated any kids with ADHD while others singled out nearly all the boys as potentially ADHD. "Teachers differ significantly in their sensitivity and tolerance for certain behaviors," says Martin Teicher, director of the Developmental Biopsychiatry Research Program at McLean.

Dr. Teicher has developed the McLean Motion and Attention Test, or M-Mat, which uses a computer to confirm an ADHD diagnosis. During the 15-minute test, the child completes a task on the computer while wearing a headband with an infrared light. The light allows a video camera to track his or her movements and fidgeting. A normal child will fidget about 1,000 times, while a child with ADHD has been shown to move three to four times more.

In children whom a doctor had previously diagnosed as having ADHD, the computer agrees about 85 percent of the time. Dr. Teicher notes that the test isn't a substitute for the opinions of teachers, parents and doctors in diagnosing behavioral problems, but that it can be useful for helping to ferret out the estimated 15 percent of cases in which a learning disability or other problem has been mistaken for ADHD. It can also help confirm whether a drug like Ritalin is working.

McLean researchers are working with a private firm to expand use of the test, which is now used in about 60 hospitals around the country. For a list of hospitals who offer the M-Mat, go to


I have a place in my heart for children with AD/HD. My son was hyperactive. At one time when I worked for the school board with children who had developmental disabilites, I would sometimes include a child who was hyperactive in a small group that was working on individual studies.

I remember one particular young boy, in a grade one class where I worked with a child with autism, was showing defintie signs of being overactive and impulsive. The teacher had talked with the parents and arranged for some testing but the parents family doctor was adament that this young man was fine and the testing was not done.

One month later he was riding his bike with his brother and went racing through a stop sign while his brother shouted for him to stop and was hit and killed by a truck. This young boy died from his impulsivity. It was very sad and I could not help but think that this tragedy could have been prevented by medication.

Medication is a necessary tool for people with AD/HD and there needs to more research into this constellation of behaviours along with better medications and screening tools.

My concern is that extremes of *underdiagnosing* as well as overdiagnosing both have consequences. Sometimes it seems that all you hear about in the media are the negative affects of medications and rarely do you see the benefits. Even more rare is seeing the negative effects of non treated AD/HD.

David Baxter PhD

Late Founder
I think you must know by now that I am certainly NOT anti-medication. The article starts out by saying, "most people agree that Ritalin and similar drugs can dramatically improve the lives of kids suffering from ADHD" and when stimulant medication works, it often does have dramatic and almost immediate benefits. Moreover, when the child is legitmately diagnosed, not to treat him with stimulants may lead to a variety of other problems, including depression and slef-esteem issues.

But it used to be the case that one did not diagnose ADHD until other potential causes of the behavior were ruled out. Today, it seems to be too often the starting point. That worries me.

And there is a sociopolitical aspect to it that also worries me: I often see ADHD effectively diagnosed by teachers -- I am also NOT anti-teachers, but some have an agenda where the primary goal is a quiet classroom rather than the well-being of the individual student. I do believe that teachers can be a valuable source of information about child behavior but they should not be telling parents, as is sometimes the case, that they believe the child "has ADD and should be on Ritalin" -- that goes beyond their areas of expertise and is often acted on by well-meaning physicians who are trying to help the child. Diagnosis should be left to competent ADHD specialists who I would hope would follow the older guidelines requiring that other origins of the "problem behavior" be ruled out first.


I was not considering that you were anti-medication, Dr Baxter. My appologies if that's how it came across. I just wanted to relay what I felt and experienced with this issue.

It is most unfortunate that there are some teachers who go too far in their personal agendas. I think these days the training for teaching is far more comprehensive then in the past so you would see less of that...I would hope.

From my experience, there has been more emphasis on incorrect or underdiagnosis. I had a principal tell me once that he did not believe in the existence of ADHD. I have also seen a child for whom the psychologist recommended an assessment for ADHD and the literature was sent home. It was two years later after failing two grades that a personal interview was done with the single dad who then took his son for a full assessment at Sick Kids in Toronto. He was dx'd and treated with medication which turned his world around 100%. It would take him two hours to even get a date on the page and with treatment he was asking for more math work.

These are the kinds of things I have experienced versus the overdiagnosis.

The very issue I have with this whole constellation of symptoms is that not enough is being done to improve matters and too much energy is being wasted on the social political areas.
I definitely think there is a degree of over-diagnosis of ADD. I'm a former special ed teacher and saw many legitimate cases, but also some definitely examples of times when teachers would refer a child or suggest that a child be tested due the difficulty that child had with fitting the mold of the classroom. And while I defintely agree that Rx drugs have their place, there are many parents who would prefer to find alternatives. I've actually found several child ADD treatments that work well as alternative to prescriptions (eg., Children's EFA Blend with omegas in it, valerian, etc.) So I think that is also an option that should also be weighed if that is the desire of the family.
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David Baxter PhD

Late Founder
Except there's little or no substantive research to support the claim that those supplements do anything useful.

Increasing Omega 3 EFAs in the diet are generally good for both physical and mental functioning, primarily by improving general cell functioning. They may help with mild cases of anxiety and depression, etc., but the majority of people who need medication and try those first end up taking the medication.
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