Finding the right ADHD medication can be tough, and there’s a lot of trial and error. Just like trying on shoes, sometimes you have to squeeze through a few narrow fits to find the right match.

But what happens if you can't quite find the right size? How do you know if your child's ADHD meds are working? And why don't ADHD meds work?

Our Guest Expert, Dr. Charles Parker, offers insight into the world of ADHD meds -- and why, sometimes, they just don’t work.

1. Measure Effectively
   According to Dr. Parker, the best way to measure medication is to look past diagnostic labels such as ADHD. "They’re static, they’re imprecise,” he explains. As representations of what is going on underneath, the official diagnosis is only a part of the puzzle. It’s important to focus on what’s happening in the person’s mind, how they manage and use information. In other words, look at the person’s Executive Function. This awareness, according to Dr. Parker, is the key to strong communication between patient and doctor.

   In order to effectively measure a medication’s impact, you have to use what Dr. Parker calls the Therapeutic Window. “Stimulant ADHD medication really doesn’t last the whole day,” Dr. Parker explains, so you only measure the effects from when you take the medication until it wears off, or from one side of the “window” to the other. If the medication works, behaviors should change during this time. If it doesn’t change, it’s time to look a little deeper.

2. How is the Medication not working?
   Many different factors can interfere with medication, so the challenge is to identify what is be standing in the way of the medication's effectiveness. Sometimes people have co-existing conditions that are completely at odds with each other. Mood disorders, according to Dr. Parker, make treating ADHD especially difficult. A stimulant that could help ADHD would only aggravate a disorder such as depression, and vice-versa.

   In this interview, Dr. Parker stresses the importance of looking at an individual’s metabolism, which can dictate how long a medication remains in a person’s system. If an ADHD med is processed too quickly, it won’t work for as long as it’s supposed to. But Dr. Parker is adamant: you can’t tell a person’s metabolic rate based on their size.

   In other words, just because a patient is large doesn’t mean they need a larger dose. It is key to understand what a dose is doing with each individual, and not make generalizations. As Dr. Parker puts it: an extremely large man can have a “very very sensitive and impossibly short burn rate.” It all depends on each person’s individual body.