What is ADHD? – A Very Brief Explanation
Attention-Deficit/Hyperactivity Disorder (ADHD) is a developmental disorder characterized by an ongoing pattern of inattention, hyperactivity, and/or impulsivity.
It’s important to note a couple of things about ADHD.
Why Treat?
Some people do not understand why ADHD should be treated, especially with medicine. Obviously most people have some moments of inattention, procrastinating, acting without completely thinking it through, feeling restless, etc, so some people have a hard time viewing ADHD as a “disorder.”
The reality is ADHD is not just a sometimes thing and is not just a “these things are kind of hard for me” thing. When someone actually meets criteria for ADHD, the symptoms are apparent and cause issues. These issues are not just limited to having more difficulty being successful at work or at school. They also impact people’s relationships. Further, studies show that people with ADHD are more likely to refuse school, use illicit substances, suffer accidental injuries, have teenage pregnancies, and get into car crashes. The good news is that treatment does not just decrease symptoms of ADHD, but has been shown to decrease these negative outcomes associated with ADHD as well.
What Are Pharmacologic Treatment Options?
There are a number of different treatment options for ADHD, including pharmacologic (medications) and non-pharmacologic (therapies). In this piece, we will talk medications…and some definitely work better than others.
We won’t talk too much about how these medications work because the reality is it’s complicated and there’s still a lot to learn both about the biological underpinnings of ADHD as well as how these treatments work.
To oversimplify, most ADHD medicines act on the catecholamine pathways. The main catecholamines are epinephrine, norepinephrine, and dopamine. These chemicals have a range of effects on our bodies and minds, including impacts on heart rate and blood pressure, mental alertness, and stress response. Different medicines impact the catecholamine pathway in different ways, and there are likely many other effects on brain cells that occur when we change the levels and concentration of these chemicals in our brains that we do not completely understand yet.
Before getting talking meds, there are a few important things to know.
Psychostimulants
The most commonly known ADHD medicines are the psychostimulants. It’s no surprise that these medicines are the ones most associated with ADHD treatment because they are the most well-studied and the most effective. Commonly used psychostimulants include amphetamine/dextroamphetamine (Adderall/Adderall XR), lisdexamfetamine (Vyvanse), methyphenidate (Ritalin/Concerta), and dexmethylphenidate (Focalin).
These medications have short-acting versions and long-acting versions, with the long-acting typically being favored. Long-acting tends to be better because it is easier to take medication less often, a person will experience sustained effects instead of potential “on/off” effects, and it is thought that long-acting versions are less likely to lead to misuse.
These medications can work pretty instantly, and effects last until the medication is metabolized. This can be a positive as the benefits are quick, and, if someone does not like something about the medication, the effects don’t have to last long. On the negative side, these medications need to be taken daily. If someone forgets the medication one day, they will know.
Side effects include elevated heart rate, increased blood pressure, tremor, cardiac arrhythmia (abnormal heart beats), difficulty sleeping, headache, decreased appetite, seizures, and upset stomach. If taken in too much quantity, these medications can cause psychosis. The most dangerous side effects, such as abnormal heart beats and seizures, are rare and occur more often in people who have a predisposition to those conditions or if someone takes too much medication.
Because of the potential impact on blood pressure and heart rate, you should get your blood pressure and heart rate checked at least annually on this medication. Luckily, those vital signs are taken at every annual appointment anyway! Depending on someone’s other medical conditions, it may also be good to get an EKG prior to taking this medication.
Overall, of the ADHD medications, psychostimulants have been shown to have the best efficacy. Because of this, unless there is some reason someone should not take a psychostimulant, these are the medications that will be used.
So why wouldn’t someone be a good candidate for a psychostimulant? Some people have other conditions, like obsessive-compulsive disorder (OCD), severe anxiety, or tic disorders, which can all be made worse by psychostimulants. Psychostimulants also have the potential to be misused and have addictive potential, so someone with an individual or strong family history of a substance use disorder may want to try something else. Other people have certain medical conditions, such as heart or neurological diseases, that make psychostimulants less safe for them.
Selective Norepinephrine Reuptake Inhibitor
Atomoxetine (Strattera) and viloxazine (Qelbree) are both non-stimulant medications in the class of medications called selective norepinephrine reuptake inhibitors. Studies have shown these medications can work well enough that they will be tried in people with ADHD who cannot take psychostimulants. These medications can be especially helpful if someone has a mood disorder as it may be a way to treat ADHD while being mindful of and perhaps making a positive impact on that other condition.
These medications can work more quickly for some (days to a couple of weeks), but many people note it can take 6-8 weeks for full effect.
Side effects include sedation, decreased appetite, erection that won’t go away, increased heart rate, elevated blood pressure, difficulty sleeping, upset stomach, difficulty peeing, decrease in blood pressure when standing (called orthostatic hypotension), sexual dysfunction (decreased sex drive, difficult achieving orgasm, erectile dysfunction), and rare potential to activate suicidal ideation or behavior.
It is important to note that Qelbree is newer and less well studied than Strattera, but some think that the side effects may be less severe.
Alpha-2 Agonists
Alpha-2 Agonists include clonidine and guanficine. These are non-stimulant medications that bind to certain receptors that impact levels of norepinephrine. Studies show these medications reduce ADHD symptoms, particularly hyperactivity.
Clonidine is short-acting and can have major side effects, particularly sedation and low blood pressure. For this reason, clonidine is not used often as a standalone treatment. Sometimes, it is used as an add-on when other medications are not working well enough alone.
Guanfacine is similar to clonidine, but because it is a little more selective with the receptor it binds to, the side effects are less severe. For this reason, it is the alpha-2 agonist that is most likely to be used.
Based on current research, guanfacine is similarly effective as the selective norepinephrine reuptake inhibitors (Straterra and Qelbree) and is less effective than psychostimulants. This medication is primarily used in kids, especially when psychostimulants are not an option.
Side effects for both guanfacine and clonidine include dry mouth, dizziness, constipation, sedation, decreased blood pressure, changes in heart rate, and stomach upset. Because these medications can have such a big impact on blood pressure, it is recommended that when taking this medication, you check your blood pressure regularly.
Buproprion
Bupropion (Wellbutrin) is a commonly used antidepressant that’s been shown to be somewhat effective for symptoms of ADHD. There’s not a ton of studies on Wellbutrin for ADHD, and the effect sizes of these studies are small to moderate. Overall, it seems much less effective than psychostimulants and perhaps even inferior to the selective norepinephrine reuptake inhibitors (Straterra and Qelbree). This medication is mostly used when someone also has depression, and there’s an attempt to treat ADHD and mood symptoms with one medication instead of using multiple.
Wellbutrin usually takes 2-4 weeks to work.
Side effects include difficulty sleeping, headache, tremor, dry mouth, weight loss, high blood pressure, constipation, and stomach pain. Rarely, Wellbutrin can also cause seizures. This is more common if someone has some other illness or is on another medication that also increases risk for seizures.
Modafinil
Modafinil (Provigil) is considered a psychostimulant, but it has a different mechanism of action than the other psychostimulants described above. Like those psychostimulants, Provigil is a controlled substance, but is classified as a schedule IV instead of a schedule II (the other psychostimulants are schedule II). This means it is thought Provigil has less addictive potential.
Provigil has been used to treat narcolepsy and daytime sleepiness related to other conditions (like sleep apnea). Because it seems to impact alertness, it was tried as a treatment for ADHD. It is not yet FDA-approved for the treatment of ADHD, but it is sometimes used off-label. Short-term randomized clinical trials have shown moderate efficacy in reducing ADHD symptoms in children and adolescents. The results in adults have been more mixed.
Because it is still a controlled substance – and seemingly less effective one – Provigil is not used as often as the other psychostimulants (like Adderall XR, Vyvanse, or Concerta). Additionally, Provigil has a range of side effects, including a risk for potentially severe skin reactions. Because of the unclear benefit in ADHD and risk for potentially severe reactions, Provigil has not been FDA-approved for this condition.
© DR. ALLISON YOUNG
© DR. ALLISON YOUNG