Thursday, May 7, 2009

Long-term stimulants & ADHD

The long-term use of stimulants such as methylphenidate (Ritalin), dextroamphetamine (Dexedrine), and mixed amphetamine salts (Adderall), in the treatment of attention or behaviour problems in children and adults, has been a controversial issue.

Symptoms of so-called ADHD include inability to sustain attention while doing academic, social, domestic, or work activities; restlessness, and inability to sit quietly or wait patiently. Of course, everyone has difficulties in these domains at times. The diagnosis of ADHD is intended to apply to individuals whose symptoms are so severe in these areas that it causes serious, ongoing problems functioning socially, academically, and with other life tasks. Those with an ADHD diagnosis are much more likely to drop out of school, to be unable to maintain jobs, to have difficulty maintaining friendships, and to have conduct problems ultimately leading to problems with the law, etc.

It is abundantly clear, from careful research, that stimulants improve symptoms of ADHD, and associated problems with social behaviour and disordered conduct.

I do not see good evidence that stimulants adversely affect personality traits or sense of self. Rather, in many cases, the experience of having severe untreated ADHD symptoms adversely affects personality traits and sense of self.

I will add to this post later, to discuss potential adverse effects from stimulant therapy. But stimulants are generally well-tolerated, with a low risk of serious adverse effects for most people.

Existing psychosocial treatments can help ADHD symptoms as well, but they do not work as well as stimulants, and--surprisingly--combining psychosocial treatments with stimulant therapy does not work much better than stimulants alone, except possibly for some individual cases. Here is some evidence, from a 2008 meta-analysis, for this finding:
Here are a few other important studies pertaining to long-term stimulant use:

This 5 year prospective study shows that stimulant therapy substantially reduces the rate of smoking and substance use disorders in adolescents with ADHD:

About 20% of ADHD adolescents treated with stimulants over 5 years developed a substance use disorder, compared to 55% of ADHD adolescents not treated with stimulants.

Stimulant-treated adolescents also had much lower rates of smoking. This is a very strong and compelling study, showing profound reductions in addictive disorders as a result of long-term stimulant treatment.

This 2008 study looked at a group of 169 children with ADHD, and followed up on them 9 years later:

The children who had taken stimulant treatment for their ADHD fared better than those with ADHD who had not taken stimulants, in terms of academic performance (as measured in several different ways). Neither ADHD group performed as well as a comparison group without ADHD.

This 2007 study from the Journal of Developmental and Behavioral Pediatrics is particularly strong, in that it looks at an entire birth cohort (all 5718 children born in Rochester between 1976-1982, of whom 370 with ADHD were identified):

It looked at long-term outcomes, over an average of 18 years. The study shows reduced absenteeism, reduced likelihood of being held back a grade, and slightly higher reading test scores, for ADHD children receiving long-term stimulant therapy.

Reading scores were particularly higher in the children who had received high doses of stimulants for longer periods of time.

The stimulant group did not differ from the non-stimulant group with respect to sociodemographic variables or duration of follow-up. The study was retrospective and was not randomized, yet it remains a very strong piece of evidence about long-term effects of stimulant treatment for ADHD.

I think these findings emphasize a number of things:
1) stimulants work very well for ADHD symptoms
2) stimulants unfortunately only have a slight effect on long-term academic outcomes
3) existing psychosocial treatments work modestly well on their own, but for most people do not add to the benefits of stimulants. The psychosocial treatments did not improve long-term academic outcomes. The duration of psychosocial treatment did not correlate with better improvement in symptoms, so the weakness of existing psychosocial treatments is not likely due to inadequate length of treatment.
4) long-term stimulant therapy may substantially reduce the risk of ADHD kids getting into alcohol use, substance use, or smoking problems. This finding is strong evidence against the idea that stimulant use increases the risk for subsequent addictive disorders.

I do think we need to keep working on better psychosocial treatments. I suspect that intensive, long-term, individualized treatment, with a style which suits the personality and strengths of each person, will be most effective. And I suspect that such treatments would need to be combined with positive, supportive milieux at home, school, work, and in peer relationships.

I will add to this post, or write a sequel post, to discuss other treatments for ADHD, such as atomoxetine, antidepressants, EEG biofeedback, dietary modification, and some newer psychosocial treatment ideas.


The ADHD Treatment Guide said...

Hi Dr. Kroeker,

Great blog, I'm glad I found it! That 2008 study you mentioned was interesting. One thing that really puzzles me is the fact that so many comorbid disorders pop up with ADHD, which often throws a monkey wrench into a lot of the medication treatment strategies. I know a lot of psychiatrists try to balance these out with other medications to treat the comorbid disorders, but, this obviously sets up a number of possible adverse drug-drug interactions or the drug for the comorbid disorders can counteract some of the effects of the ADHD medication. This is why I'm such a big fan of integrating with adjunctive behavior therapy treatments instead of simply trying to throw a bunch of medications at all of the comorbid symptoms and disorders. I definitely agree with your concluding paragraphs. Keep up the good work!

Anonymous said...

I can't find another post on ADHD, so I don't know if you are still planning to add to this post or write a sequel post...

I have a few questions about this:

1) You write here that long-term use of stimulants has NOT been shown to improve long-term academic outcomes. Why do you think this is, given that symptoms of ADHD improve on medication? (It actually really depresses me to think that individual symptoms can improve, yet no real change takes place...though I know that this might not apply to all patients.

2) What are some effective non-drug treatments for ADHD? I am particularly interested in dietary measures, and also EEG biofeedback.

3) I have read about prescribing psychostimulants as a way of basically diagnosing ADHD...i.e., the diagnosis is based on your response to the medication. I am just wondering how precise this would be, given that stimulants would probably (?) impove most people's concentration, etc. Or is there any role for neuropsychological testing in trying to establish a diagnosis? Is there any way of definitively establishing this kind of diagnosis?

4) I have read that there are many differences between ADD and ADHD, i.e. not just in symptom presentation but in the underlying brain pathology. Is that true? I'm not sure how to phrase it, it seemed like the suggestion was that ADD was more "organic", although maybe that doesn't make sense. Does that have implications for prognosis or treatment strategies?

5) I have read that one red flag that suggests ADD in the context of MDD treatment is a good response to bupropion. If a patient did not have a really good response to bupropion-- or if the response was only partial-- does this usually mean that treatments with psychostimulants like Ritalin, Adderall, etc. will be ineffective (or only partially effective) also?

6) If ADD is not diagnosed/treated until adulthood, is it usually more difficult to treat than if it is diagnosed/ treated in early childhood? Is the response to stimulant treatment just as good? I guess I am wondering if there are certain structural changes that occur in the brain that result from untreated ADD-- kind of like long-term depression and hippocampal atrophy?

7) Is there a certain type of patient who usually does poorly on psychostimulants, or who experiences severe side effects on psychostimulants?

Thanks in advance!