You might be saying to yourself, okay, ADHD is probably overdiagnosed. And yes, some people who are on a stimulant probably shouldn’t be, like the college student struggling to focus on a boring lecture or the kid who’s fidgeting a bit too much for his teacher’s liking. But how can it be that among the millions of people diagnosed—over 4 percent of adults and 11 percent of children in the U.S.—not one of them actually has ADHD? Because we’ve all encountered someone with severe attention or hyperactivity issues—the boy who is always daydreaming, the girl who gets out of her seat to run around the room while her classmates sit calmly, the woman who consistently asks questions that have just been answered. Surely at least some of these people have ADHD! Actually, not one of them does. Let me be clear: In my view, not a single individual—not even the person who finds it close to impossible to pay attention or sit still—is afflicted by the disorder called ADHD as we define it today.

Ever since 1937, when Dr. Charles Bradley reported that children who exhibited symptoms of distractibility responded well to stimulant medication, the core concept of ADHD has remained essentially unchanged. Imagine, despite decades of advancement in neuroscience, we’re still approaching this “disorder” the same way.

You may notice that there is something striking about the way we define this “illness”—that is, by its symptoms, rather than its cause. If we were to define a heart attack by chest pain, then the appropriate cure would be painkillers, rather than the revival and repair of the heart. Other examples are easy to find: Nasal congestion can be a symptom of a cold, allergy, or many other conditions, but a runny nose is not a diagnosis. In the same way, the symptom complex associated with the ADHD diagnosis is related to more than twenty medical diagnoses, (from those as mild as poor eyesight, sleep deprivation, and even boredom in the classroom, to more severe conditions like depression and bipolar disorder), that, when treated effectively, can result in the disappearance of the attention-deficit and hyperactivity symptoms. But before I make this case, allow me a brief digression into the mechanisms by which common medications for ADHD work.

The stimulants most often prescribed for ADHD represent several different types of agents that help control attention and behavior. These include methylphenidate (like Ritalin and Concerta) and mixed salt amphetamines (like Adderall and Vyvanse). Each of these has a specific effect on the body’s neurotransmitters, or the chemical compounds that help transmit signals within the nervous system. The exact mechanisms by which these chemicals interact are very complex, but essentially, if levels of these chemicals are too low or their activity is blocked, the transmission of messages within the nervous system decreases, corresponding to a state of inattention or impulsivity. Specific medications aimed at targeting attention-deficit and hyperactivity symptoms help increase levels of neurotransmitters and their activity. For example, methylphenidate-based medications like Ritalin increase the activity of the neurotransmitters dopamine and noradrenaline in the parts of the brain that help to control attention and behavior. Adderall also increases dopamine’s effects, but in a more gradual way than Ritalin and similar agents do.

So let’s back up a moment. If stimulants can increase one’s attention span and reduce impulsivity, why shouldn’t we use them? Furthermore, even if we’re masking another underlying condition, aren’t we at least solving the problems of inattention and impulsivity in the patient? The answer to both of these questions is a resounding NO. While stimulants can help people with a variety of symptoms in the short term, they have multiple damaging effects in the short- and long-term. The most common short-term side effects associated with stimulants involve overstimulation, such as loss of appetite and sleep disturbance, but perhaps more troubling are the longer-term effects of stimulant use, which include unhealthy weight loss, poor concentration and memory, and even reduced life expectancy in some cases. Long-term, patients also face the development of tolerance, which exacerbates these side-effects. After a while, the body adjusts its natural production of these same chemicals in the brain, and the temporary improvements in attention and behavior begin to disappear. This is why we see doctors prescribing higher and higher doses of the stimulant to achieve the same effect in the patient as time wears on—a dangerous pattern.