The Journal of Clinical Psychiatry just came out with a large study showing a correlation between ADHD medications and reduction in height in teenagers, however, the issue is very complicated. The study appears to have a lot of potential flaws. Since I work with so many children and teenagers with ADHD, I want you to know I stay on top of the latest research. This moonth's front page article definitely makes headlines, but if you read the fine print, there's more than meets the eye. Here are just some of the issues I've found. Check out this PDF.
1) pg 7. “Our sample included only male patients and their relatives, and might not generalize to female patients.”
2) pg 7. “A full mechanistic understanding of why...individuals with ADHD are shorter than expected is currently lacking.” The authors don't know WHY ADHD and height is correlated.
3) pg 7. Unclear hypothesis. “There are indications that children with ADHD have an increased risk of growth hormone stimulations...(but) the etiology (is not) fully known.”
4) pg 8. Only yes/no answers were permitted, so they only asked if the child took ADHD medication or not. They did not record length of time on ADHD medication, dosages, or which types.
5) pg 8. Other contributing factors. “The associations between ADHD and shorter height were partly explained by socioeconomic status (financial stability, net worth, etc), prenatal care, and other psychiatric factors.”
6) pg 6. Improper end point. The authors didn't know when to stop measuring height. They did not take into account puberty and growth spurts. The cut-off age was arbitrary, in other words, the children may still have been growing.
7) pg 6. Generalization. The study was only done in Sweden and only with males. One has to be careful generalizing those results to females and to the rest of the world could be problematic. It's just one country, and one gender.
8) Pages 6-8. Many other studies have proven no correlation.
Lastly, to reiterate, no proven causation was found, just a correlation. And the max correlation was about 1 cm. That's 0.39 inches. When all is said and done in this study, it’s not even that much.