TCPR: How does stimulant treatment differ in adults versus children with ADHD?

Dr. Diller: The benefits are similar, but the risks are different. With young children, I worry about side effects like appetite loss, insomnia, and growth retardation. In adults, I worry about medication misuse. Children don’t like high doses, but some adults do, and adults can control how much they take in a way that children can’t. What that means is medication misuse is a bigger risk in anyone over age 14 or 15 (Wolraich ML et al, Pediatrics 2019;144(4):e20192528; Schepis TS et al, J Clin Psychiatry 2020;81(6):20m13302).

TCPR: What happens when the dose goes too high?

Dr. Diller: In children, once the dose goes beyond the upper limits of the PDR—I’m talking about amphetamine salts beyond 60 mg/day or methylphenidate beyond 72 mg/day—I start to see agitation, anxiety, and irritability (Graham J and Coghill D, CNS Drugs 2008;22(3):213–237). They perseverate—they get hyperfocused and rigid in their ideas. They talk a lot (logorrheic). Overall, their cognitive performance starts to deteriorate when the dose is too high. That can happen in adults too. There’s not much added benefit in going beyond the maximum recommendations. If the patient isn’t responding, it’s better to change to a different stimulant or preparation.

TCPR: How do you dose stimulants?

Dr. Diller: I run a titration trial where I ask patients to test out three dose levels, trying each level for three days. The exact doses will depend on the patient, but might typically involve Concerta 18, 36, and 54 mg/day. If they feel anxious or can’t sleep at a higher dose, I lower it.

TCPR: What do you tell the patient to look for in terms of improvement?

Dr. Diller: I find something measurable that the patient agrees is important in their life. Maybe their homework used to take two hours, but now it only takes one hour. They’re not as behind in their email inbox. They finish their reports at work on time. Their spouse says there’s a greater feeling of connection during conversation. Measurable outcomes like those are much more reliable than “I feel more focused.” Typically, I’ll evaluate their response to a stimulant over a two- or three-month period.

TCPR: Do you get input from family?

Dr. Diller: Yes, that is immensely helpful. Stimulants—particularly the amphetamines—can boost confidence, and this gives patients an inflated sense of how they are doing. I usually invite the spouse or the significant other in at the six-month mark, and sometimes at the initial evaluation as well. 

TCPR: How do you make the diagnosis in adults?

Dr. Diller: I don’t tend to use checklists or structured interviews where the patient answers “yes” or “no” to DSM symptoms. It’s more important to find out how the symptoms are affecting them. I’ll ask questions like, “What is the problem? How does it manifest in your life? What have you tried to do about it, and how does it affect other people?” 

TCPR: And if their problems match up with enough DSM symptoms, do they have ADHD?

Dr. Diller: Well, you have to rule out other causes, particularly in adults, like mood, anxiety, and sleep disorders, as well as brain injury and medical problems that might be affecting their cognition (Wolraich et al, 2019). To meet DSM-5 criteria, you also have to trace the symptoms back to before age 12. Sometimes the problem is not ADHD. It may be a learning or processing disorder, in which case the problem is more limited in scope, like they have to read a text two or three times to comprehend it. Sometimes there is a mismatch with their temperament or talents and what they are trying to do, like a creative soul who is trying to study accounting. Some patients think they have ADHD because they are perfectionistic. They set up unrealistic goals, juggling career and family and school and more at the same time (Anbarasan D et al, Curr Psychiatry Rep 2020;22(12):72). 

TCPR: Will a stimulant trial clarify the diagnosis?

Dr. Diller: No. There’s a myth that people with ADHD have a different response to stimulants than the general population. Children and adults, ADHD or not, will stick with things longer on a stimulant. They are more steady, deliberate, and methodical. That’s the main reason they look calmer on them. They are not sedated. They are less impulsive. I tell children they’ll have a few seconds longer to think through things before doing something dumb. They help people follow through on their priorities and provide a bit more energy too. There can also be a mild euphoric effect, which is one reason people use them recreationally.

TCPR: Do you see any important differences between the methylphenidates (eg, Ritalin, Concerta) and amphetamines (eg, Adderall, Vyvanse)?

Dr. Diller: Amphetamine is a bit more intense than methylphenidate. The largest meta-analysis so far—from the Cochrane group—concluded that amphetamines work a bit better for adult ADHD and methylphenidate works a bit better for those under 18, but the side effects are also a little worse for the amphetamines, particularly insomnia (Cortese S et al, Lancet Psychiatry 2018;5(9):727–738). I’ll generally start with methylphenidate unless the patient has a family member who did better on amphetamine. But if they don’t respond, I’ll switch to the amphetamine class. 

TCPR: There are 30 stimulant formulations. Which do you start with?

Dr. Diller: That’s probably more than we need. Every other country gets by on five formulations! For me, the standard choices are Concerta, Adderall XR, and Vyvanse, all of which are now generic. I don’t see an advantage with dexmethylphenidate (Focalin) over methylphenidate. Outside of that, I have a few child patients and even a few adults who prefer the patch, which offers more control over stopping effects by removing it sooner. The new extended-release liquid formulations are good for those who have difficulty swallowing (Editor’s note: Methylphenidate comes as a Daytrana patch, which carries a risk of allergic skin reactions, including discoloration. Dextroamphetamine is available as a new Xelstrym patch. For XR liquids, methylphenidate comes as Quillivant and amphetamines come as Adzenys and Dyanavel).

TCPR: What is going on with the stimulant shortage?

Dr. Diller: That started with immediate-release Adderall in the fall of 2022, and it spread to other amphetamine formulations and to methylphenidates as the shortage forced patients to switch from Adderall. The reasons are several. Telehealth increased access to stimulants, and there was a labor shortage during the pandemic that impacted manufacturing (www.tinyurl.com/2rr2dwst). I suspect patients are now hoarding the drug out of fear of not being able to obtain it when needed. Meanwhile, the US government determines an annual quota, but that’s not the reason for the shortage. Most of the companies haven’t used their full allowable quota this year. 

TCPR: How much does the government allow?

Dr. Diller: In 2022, they allowed 133,525 kilograms (147 tons) of stimulants, which equates to 405 mg of stimulants per year for every person living in the US. No other country comes close to that (www.tinyurl.com/yc796sxj). Most are using 4%–5% of what they use in the US. 

TCPR: That’s like forty 10 mg Adderall tablets for every US citizen.

Dr. Diller: Yes, and there’s a major illegal market of the legally produced drugs. Based on a 2015 telephone survey from the National Institute on Drug Abuse, around 5 million Americans obtained stimulants illegally, and 400,000 reported behavior that was consistent with abuse and addiction. When we look specifically at young adults—the 18–29 age group—13% had tried a stimulant and 6% had used the stimulant illegally or had gotten it from a friend. However, people who get the prescription legally from their doctor have much lower rates of misuse and abuse than those who get it from a friend.

TCPR: How do those numbers compare with other substances?

Dr. Diller: In terms of abuse rates, the 400,000 represents about a quarter of those who were reporting opiate addiction at the time. The main difference is you don’t generally die from stimulant abuse as quickly as you might die from opiate abuse. But stimulant misuse is often accompanied by the misuse of other substances, and amphetamine’s highs and lows are reputed to be even more unpleasant than those from opiates. 

TCPR: What does this mean for practice?

Dr. Diller: When your patient with ADHD goes off to college, you have to tell them, “It’s not a bad thing that you’re taking a medication, but you can’t tell your friends that you take a stimulant. Otherwise, they will ask for one during exam time or steal it from you. Giving stimulants to other people is illegal for you and for them, just like dealing drugs is illegal, and when people take it illegally, they are much more likely to develop problems.”

TCPR: Are some formulations more likely to be misused?

Dr. Diller: Yes. Immediate-release Adderall is the preferred formulation for getting high. Even when people are using it to treat ADHD, they can get into habits of misuse with the immediate release, like skipping a few days and then taking double or triple their dose to pull an all-nighter. With the extended release, that is much less likely. No responsible clinician should be prescribing immediate-release stimulants to the teenage and adult population.

TCPR: What if they skip the dose on weekends?

Dr. Diller: I’m fine with that. I’m also fine with taking a break in the summer. What I want for my patients is a consistent pattern of use, not random PRNs. With a college student, I’ll count out their pills and determine their proposed pattern of use (every day, five days a week, etc). They then must get back to me within a two-week refill window when they should have no more medication. I’m trying to avoid a problem I’ve noticed where I wouldn’t hear from them all semester and then suddenly before exam time, they request a refill after bingeing on them. I felt like I was facilitating an ADHD lifestyle. 

TCPR: What are your top behavioral interventions for ADHD?

Dr. Diller: For children, the main intervention is parent training. A good place to start is the book 1-2-3 Magic by Thomas Phelan (Naperville, IL: Sourcebooks; 2016). The book teaches parents to respond to problem behaviors with less talk and more action—immediate consequences. For older kids, organization is more of a problem. The most useful thing there is hiring a high school or college student to come in for an hour a few days a week and help them get the homework done. You don’t need a fancy tutor to teach organizational techniques that the kid is unlikely to use. Just the presence of an older mentor that they look up to is motivating enough for many, and much more affordable. Another useful intervention is to find a school program that includes a 45- to 60-minute study hall where they can get the homework done with a teacher present. 

TCPR: And interventions for college students?

Dr. Diller: College students can get a variety of accommodations, from extra time on tests to no penalties for late work. Individual counseling or ADHD coaching is helpful, but it’s a mixed bag on whether the student will follow through on the advice. Many do not have the self-discipline or consistent motivation to succeed in college. Screen time and video games become a problem. Video games are designed for the ADHD mind. Everything is immediate; there’s no delayed gratification. 

TCPR: Do you then recommend lifestyle interventions like exercise?

Dr. Diller: Yes, improve, but for many we need to start with something more basic (Dastamooz S et al, EClinicalMedicine 2023;62:102137). Just getting them out of their dorm room and physically and socially engaged with life is the first step. 

TCPR: How do you work with “failure to launch”—the young adults who don’t go to college and still depend on their parents?

Dr. Diller: I emphatically tell those patients they are going to have to get good at suffering. They have to wait until their suffering increases enough to motivate them to get over their anxiety and take action. That point usually comes as they see their peers moving forward where they are not. It’s a bit paradoxical in intent, but it’s honest. “I think you’re going to have to suffer more here before you make the decision to find a job.”

TCPR: What do you tell the parents?

Dr. Diller: I’ll say, for example: “I don’t think you can make your son mature faster. That is up to him. You can delay his maturation by making things easier for him, like paying for his credit card or rescuing him repeatedly.” This is tough for the parents because they feel responsible for the suffering. I’ll offer the young adults individual therapy, but only if they’re genuinely interested in changing. Unfortunately, they may have to go through that period of feeling like a failure for a while, and they don’t like it.

TCPR: Thank you, Dr. Diller.