Need for Speed?

 

Clinicians began using stimulant medication to treat hyperactivity in the 1950s. Since then, the manufacturing of stimulant medications has ballooned into a massive 10 billion dollar industry. This growth is unsurprising when one notes that the number of ADHD diagnoses has also been growing steadily since the 1990s.  Although most of the psychiatric community touts stimulant medication as both safe and effective, it remains a controversial issue in both academic and non-academic circles. Those who oppose the use of stimulants in children claim that the ADHD diagnostic criteria pathologize behavior that is within the normal range for children. Additionally, some researchers suggest that studies on the safety and efficacy of pharmacological interventions are biased in such a way that they could cause them to underestimate the risk of dangerous side effects. So, are these objections well founded, or are they bogus?

What stimulant medications do

For kids with ADHD, stimulant medications can cause a marginal increase in reading comprehension scores on standardized tests, a small decreased probability of absenteeism, and a slightly decreased likelihood of being held back a grade. However, there isn’t much evidence that stimulant medications increase academic success in the long term, and the overall effects on academic performance are small. There is one thing these drugs do pretty well. They make kids less rowdy and easier to deal with. 

Are stimulants safe?

Since the educational benefits of stimulant medications are pretty marginal, you would assume that they must be very safe since, for the benefits to outweigh the costs, the risks would have to be minimal. And that’s certainly how it seems if you don’t look too closely at the studies. The consensus of all clinical trials is those stimulant medications when taken in clinical doses, don’t have the nasty side effects typically associated with stimulant abuse(e.g. cardiovascular diseases, Raynaud’s syndrome,  decreased attention and executive functioning). Here’s the problem. No rigorous studies have been done on a long enough time frame to rule out the risk of significant side effects in the long term. A review of pre-market studies on stimulants approved by the FDA to treat ADHD found that the median length of the study was only 4 weeks. That’s clearly not lot long enough to eliminate the possibility of long-term side effects, which is a huge deal, because many children take these medications for their entire academic career and often even afterward.

Studies have shown that the medications most commonly used to treat ADHD (methylphenidate, amphetamines, and atomoxetine) increase blood pressure and heart rate. While the researchers considered the increases to be clinically insignificant during the course of a study, that doesn’t rule out the possibility that the cumulative effects of taking stimulants for years on end could put kids at risk for cardiovascular diseases. 

This is not the only potential risk of prolonged stimulant use. Through a process known as paradoxical decompensation, drugs intended to produce a certain psychological state in the short term may reduce it in the long term. Because the brain wants to maintain equilibrium, it will try to counterbalance the effects of any mind-altering chemicals. This leads to tolerance, and eventually, people become dependent on the drug to maintain their baseline. Through this process, medications may actually worsen ADHD symptoms in the long term. Some researchers have gone so far as to suggest that the prevalence of stimulant use may be causing an increase in ADHD symptoms in the population. 

Bad incentives

Given the glaring gaps in the scientific literature, why is it that ADHD diagnosis and the use of stimulants are still on the rise? One possible explanation is that the government incentivizes schools to increase the number of students that are labeled as learning disabled. According to the Americans with Disabilities Act, schools can receive funding according to the number of children in the school with disabilities. So, schools may try to increase the number of children with an ADHD diagnosis. This may also lead to increased ADHD diagnoses, especially in underprivileged communities, where school administrators are particularly desperate for funding.

There are also perverse incentives in medical research that may lead researchers to exaggerate benefits and ignore the potential side effects of stimulant drugs. A Cochrane review found that 96.8% of randomized placebo-controlled studies of stimulant treatment in children with ADHD have a significant risk of bias (Storebø, 2015). Medical researchers and institutions often risk losing funding if they speak out critically about medical interventions that make drug companies a lot of money. Enticing positions within the pharmaceutical industry will be permanently closed to those who speak out. Additionally, there may not be enough research money outside of the pharmaceutical industry for long-term studies that challenge the current wisdom on ADHD treatment.

One of the possible reasons why so many parents simply consent to the recommended course of treatment is the amount of trust they have in doctors. According to Gallup, medical doctors are the 3rd most trusted professionals, just behind nurses and engineers. Because people have so much faith in their physicians, they accept their opinion that stimulants are not risky, even though they would never normally balk at the idea of giving their children speed. It may also provide a seductively easy solution to their kids' behavioral problems. Their is a mutitude of underlying conditions that can cause the symptoms of ADHD, including depression, anxiety, and trauma. These are complex issues that are hard to deal with, and coming up with an easy short-term solution may be a very tempting alternative to spending a lot of time and emotional energy helping children to sort through their issues and develop healthy, productive behaviors and cognitive patterns.

To sum things up

Clinical studies of stimulant treatments have not been done in a long enough time frame to rule out long-term side effects. As such, the marginal benefits provided by these medications do not justify the extent to which clinicians prescribe them. Given what we know about amphetamines, the null hypothesis of any clinical trial should be that they can cause damage in the long term. The lack of long-term data would seem to indicate that medical researchers believe the burden of proof to be on the detractors of the medication. The human body is a very complex system, and it is difficult, if not impossible to model the long-term effects that any physiologically active substance will have on it. This is why there is a great need for longitudinal data on the impact of clinical doses of stimulant medications. If there are a reasonable number of these studies done, and it turns out that stimulant medications have no noticeable side effects across a human life span, then I will be the first to rejoice that the medical community hasn’t been harming children for the last 50 years. However, you should probably look for other options to curb your kid's hyperactive behavior.