TCR: Dr. Prince, you have done innumerable evaluations of children and adults with ADHD. These days, psychiatrists in the community are besieged by patients wanting treatment for ADHD, and the pressure is on to come up with a diagnosis and treatment during a single 45 minute session. Is this possible?
Dr. Prince: That’s a great question, and with kids, that’s often possible, as long as you get documentation from school and you’ve got what seems like reliable information from the parents. I usually ask parents to bring copies of school records, teacher comments, and any other psychological evaluations, such as a CORE evaluation (a state-funded special education evaluation) or neuropsych testing, if available. I also get permission to obtain records from the pediatrician.
TCR: What about a Connors Scale?
Dr. Prince: That’s good to have, but we prefer the ADHD Rating Scale (both Current and Past), which takes the DSM-4 ADHD criteria (all 18 items) and puts them on a Likert scale. Generally, I recommend that clinicians use this scale to obtain information about specific ADHD symptoms within the context of the DSM-4. In addition, you have to document the necessary number of symptoms, establish that the symptoms are developmentally inappropriate, that they begun (at least in part) before the age of seven, that they have been present for more than six months in two or more settings and that they cause significant impairment. When using these criteria the diagnosis is fairly easy to make in kids during a single session. But it’s a different story with middle-schoolers, adolescents and adults.
TCR: Why’s that?
Dr. Prince: Because you’ve got to document the onset of symptoms in childhood and the persistence of them. And you are also more likely to see comorbidities, like depression, OCD, and substance abuse. With substance abuse in particular we have to sequence the treatment, dealing with the substance abuse first, and then treating the ADHD. In these patients you’ll often move toward Wellbutrin or Straterra in order to stay away from abusable stimulants.
TCR: Why are we getting so many calls from adults who want an ADHD evaluation?
Dr. Prince: Partly this is due to the recent recognition of how heritable ADHD is. The heritability coefficient is 0.8, which makes it more heritable than bipolar disorder and about as heritable as height. Often the adults that I see with ADHD are parents of the kids I treat.
TCR: In my experience many adults will say they were never diagnosed with ADHD as kids but remember being rambunctious or dreamy, and as a clinician you’re left scratching your head.
Dr. Prince: Sure, and so it’s very reasonable to do a couple of things with adults. One is to ask them to get documentation—their parents may have kept report cards, or their siblings or other relatives can write up something about how they were as kids. A lot of these kids had nicknames, like “Hyper Harry”, or “Destructive Mary”. You can also use an excellent rating scale called the CAARS—Connors Adult ADHD Rating Scale—which incorporates not only DSM-4 symptoms but also some functional problems.
TCR: So, the bottom line is that it’s complicated to diagnose ADHD in adults.
Dr. Prince: It’s a really, really hard task, especially in 45 minutes!
TCR: So it’s not reasonable to say, “Well, I’m not really certain you have ADHD, but let’s go ahead and treat you and see how you do.”
Dr. Prince: No, because response to stimulants doesn’t mean anything. Everybody responds to stimulants in some capacity, and lack of response to stimulants doesn’t mean you don’t have ADHD. An analogy would be that if we all wore a hearing aide we’d all probably hear a little better, but not everybody needs a hearing aide.
TCR: Now, let’s get into treatment. Let’s say I have someone who I want to treat with a stimulant. How do I decide which stimulant to use?
Dr. Prince: I’d recommend that your readers obtain the treatment guidelines published by The American Association of Child and Adolescent Psychiatry in 2002 [Practice Parameter for the Use of Stimulant Medication in the Treatment of Children, Adolescents and Adults JAACAP (2002) 41 (2) suppl 26S-49S]. There are two basic kinds of stimulants—methylphenidate and the amphetamines. They work a little differently, and in general about a third of people will respond better to either amphetamine or methylphenidate. In selecting them, I start with the longer-acting agents. Among the long-acting versions of ritalin, I’m choosing among Concerta, Ritalin LA and Metadate CD, and I typically will begin with Concerta because it’s been around the longest and has the longest coverage. Concerta is a 12 hour medicine; Metadate CD and Ritalin LA are 8 hour medicines.
TCR: Do you use short acting Ritalin as well?
Dr. Prince: Yes, I have a number of adults who prefer short acting Ritalin because they want to have their dose exactly when they need it. The most recent addition to the short acting forms of methylphenidate is Focalin, which is the purified dex-methylphenidate isomer. This is the isomer that is actually active at the dopamine transporter systems in the brain, whereas levo-methylphenidate is what causes the cardiovascular side effects of Ritalin. Focalin is pure dexmethylphenidate, so 5 mg of Focalin is going to be equivalent to 10 mg of Ritalin.
TCR: So is Focalin better than Ritalin?
Dr. Prince: The jury is still out on the benefits of Focalin. There is some data coming out soon suggesting that Focalin lasts longer and has fewer side effects. And within the year there will probably be a long-acting version of Focalin introduced. But Ritalin remains a really good medicine.
TCR: What about the long-acting amphetamine stimulants?
Dr. Prince: Adderall XR is a mixed amphetamine salt which lasts about 10-12 hours, and Dexedrine Spansules last about 8 hours. I usually start Adderall as the shorter-acting version rather than XR, because for some people Adderall once a day is sufficient. Probably half my patients on Adderall can get by taking it once a day, and for the rest, I have them take Adderall XR.
TCR: Generally speaking, how to you choose between an amphetamine and methylphenidate?
Dr. Prince: There are a few issues. In adolescents, if I’m worried about abuse I’ll go with methylphenidate. One of the good things about Concerta is that it’s very difficult to abuse because of the way it’s made. If someone has a family member who has responded to a particular stimulant, that would also influence my choice. If someone has anxiety and depression, I worry a little bit more about amphetamine exacerbating it than methylphenidate. But most typically, for treatment-naive patients I will try them with each medicine. I’ll tell them at the outset that we’re going to do a “Pepsi-Coke challenge.” They’re both colas, and we’re going to try this one for a week or two, then the other one for a week or two. I do this because I’ve had the experience of seeing patients who respond well to a stimulant, but then we try something else 4 or 5 years later and it works even better.
TCR: How do you suggest we dose stimulants?
Dr. Prince: If you were to draw a graph, with reponse on the Y axis and dose on the X axis, what you typically get is an inverted “U”, where people will do better and better on higher and higher doses up to a point, and then a higher dose actually makes things worse, so you want to start with a small dose and taper up. You can be very aggressive about dosing, as long as you’re monitoring sleeping, eating and anxiety level. With methylphenidate I’ll typically target 1 mg/kg/day and with amphetamines 0.5 mg/kg/day. But it really varies. I have a 250 lb. man who is doing well on Dexedrine Spansules 5 mg per day, and I have a 9 year old who’s taking upwards of 150-200 mg of Ritalin per day. With Concerta, frequently I’ll have someone on 72 mg a day even though the highest approved dose is 54 mg a day.
TCR: What about Straterra?
Dr. Prince: I’ve had a lot of experience with it because I was involved in the first studies in the U.S. in 1995. It is a highly specific and selective reuptake inhibitor for norepinephrine; the risk of tics is really minimal, and it’s not a controlled substance because it doesn’t seem to be addictive. At this point there are not any good head-to-head studies comparing it with stimulants. In my experience, there are some people who respond better to atomoxetine, and some who respond better to stimulants, and then I have some patients who actually take both.
TCR: Can straterra be combined with SSRI’s?
Dr. Prince: Yes, but just be aware that it is metabolized by the 2D6 liver enzyme so if someone is taking an inhibitor of 2D6 like paroxetine or fluoxetine, you may want to start at a lower dose.
TCR: How do you dose Straterra?
Dr. Prince: The manufacturer recommends that you start at 0.5 mg per kg per day for 4 days, then go right up to 1.2 mg per kg per day. But I typically start a little lower than the recommended starting dose in order to get improved tolerability—the most common side effect being upset stomach. I also find that it takes longer to kick in than the stimulants, in the range of a week or two.
TCR: Do you think it treats anything else?