Medicines are a big part of the treatment for attention deficit hyperactivity disorder (ADHD). Stimulant drugs act on brain chemicals like norepinephrine, which is part of your body's noradrenergic system.
Increasing levels of these chemicals improves symptoms like inattention, impulse control, and memory problems to help you function better day to day. Your doctor can help you find the right treatment for your ADHD, which might include stimulants or other medications.
What Is ADHD?
ADHD is a common childhood mental health disorder. It involves symptoms like trouble focusing and paying attention, and sometimes hyperactivity and trouble controlling impulsive behaviors.
Some children grow out of ADHD. Others continue to have symptoms as adults, or don't get diagnosed until they're adults.
Treatment for adult ADHD often includes a combination of:
- Counseling or therapy
- Skills training
Many ADHD medicines target the noradrenergic system in the brain.
How Is the Noradrenergic System Involved in ADHD?
Your brain contains about 100 billion nerve cells, or neurons. Chemical messengers called neurotransmitters travel from neuron to neuron to help different areas of your brain "talk" to each other.
The noradrenergic system makes and releases the neurotransmitter norepinephrine. This chemical helps you stay awake, pay attention, and think clearly. Norepinephrine also acts as a hormone during your body's "fight-or-flight" response. It helps your body prepare to either deal with a threat, or run away.
Experts think that an imbalance in the noradrenergic system is one cause of ADHD. Too little of this hormone prevents signals from traveling to parts of your brain like the prefrontal cortex, which handle executive functions such as attention, emotion regulation, and impulse control.
Having too little norepinephrine and another brain chemical called dopamine could lead to ADHD symptoms like hyperactivity, trouble paying attention, and impulsive behaviors.
How Do Noradrenergic Medicines Treat ADHD?
Noradrenergic medicines work, in part, by increasing the amount of norepinephrine in your brain. These medicines come in two types: stimulants and nonstimulants.
The stimulants methylphenidate and amphetamine are the main medicines doctors prescribe to treat ADHD. These drugs increase the amount of norepinephrine in your brain by stimulating certain cells to make more of it. That's how they got their name, "stimulants."
Stimulant medicines also increase levels of another neurotransmitter called dopamine, which is part of the dopaminergic system. Your body uses dopamine to make more norepinephrine.
Psychiatrist Charles Bradley first discovered that stimulant drugs help with executive function in the 1930s, when he gave children the amphetamine sulfate benzedrine to treat their headaches. To his surprise, the children's learning and behavior improved dramatically while they were on the drug. Methylphenidate has been part of the treatment for ADHD since the 1960s.
Methylphenidate medicines include:
Amphetamine medicines include:
These medicines come in short-acting, intermediate-acting, and long-acting forms. Extended release, or XR versions, move slowly into your body over a few hours.
Extended-release capsules (Qelbree) are nonstimulant noradrenergic agents. They belong to a group of medicines called selective norepinephrine reuptake inhibitors (SNRIs).
Atomoxetine hydrochloride and viloxazine also increase norepinephrine levels in areas of your brain like the prefrontal cortex, but they do it in a different way than the stimulants.
These nonstimulant drugs block a structure called the norepinephrine transporter (NET) in nerve cells. Blocking the NET stops nerve cells from taking in as much epinephrine, which leaves more of this chemical free in your brain.
Studies show that stimulant and nonstimulant medicines improve ADHD symptoms like impulse control, memory, and attention.
How Are They Different From Other ADHD Medications?
A few other medicines also treat ADHD. Clonidine (Kapvay) and guanfacine (Intuniv) are alpha-2 adrenergic antagonists. They're thought to work by mimicking the action of norepinephrine on receptors in the prefrontal cortex.
Bupropion (Wellbutrin) isn't approved to treat ADHD, but some doctors prescribe it off-label for that purpose. Wellbutrin may relieve ADHD symptoms in some people who take it.
How Does Your Doctor Decide Which Medicine Works Best for You?
The best ADHD medicines are about 80% effective at relieving symptoms. The trouble is, doctors don't know exactly who will respond to which types of medicines. Finding the right treatment is a process that involves some trial and error.
You'll probably take a stimulant first, since those are the medicines doctors prescribe most often to treat ADHD in adults. Your doctor will start you on a low dose and then increase the dose if you don't respond. If the first medicine you try doesn't help your symptoms, your doctor might switch you to another ADHD drug.
It can take about 3 to 6 months to find the medicine that relieves your ADHD symptoms but doesn't cause too many side effects. Even the best ADHD drugs aren't perfect. To get the symptom relief you want, you may have to add other treatments like therapy, coaching, and exercise to medications.
What Are the Side Effects?
Both stimulants and nonstimulant medications can cause side effects. Some people won't have any problems while taking these medicines. Others will have problems that bother them enough to stop taking the drug.
Ask your doctor what to expect when you get a new medicine or dose, and what to do if you have side effects.
The most common side effects from stimulant medications are:
- Trouble sleeping
- Appetite loss
- Weight loss
- Headaches and stomachaches
- Moodiness and irritability when the medicine wears off
Some of the side effects that can happen with nonstimulant medicines include:
- Appetite loss
- Weight loss
- Mood swings
Let your doctor know if you have these or other side effects. Some will go away once you've been on the medicine for a while. If the side effects don't go away and they bother you, your doctor can change the dose, switch you to a different drug, or have you take it at a different time of day.