ADHD and its impact on Growth

by on December 11, 2014

in Monthly


At this time of the year a number of students discover that they cannot maintain their concentration at school. The possible diagnosis of an Attention Deficit/ Hyperactivity Disorder (ADHD) gets raised by teachers ; perhaps later this controversial condition is confirmed by a doctor or a psychologist.

Many families agonize over treating a child with ADHD, using prescribed medications. There are concerns that using stimulant medications may impair the height or increase the weight. Up until now no longitudinal population-based studies have examined height into adulthood for childhood ADHD cases.

In order to get more clarity on how these medications impact growth, researchers from Boston Children’s Hospital, the Mayo Clinic and Texas Children’s Hospital pooled their efforts. Clinicians were able to follow ADHD patients from childhood well into their early adulthood. They concluded that neither ADHD itself, nor treatment with stimulant medication is associated with significant deficits in height into adulthood. (The study, which drew a lot of attention, was published in a recent edition of Pediatrics, Vol 134, Number 4)

It is known that stimulant medications suppress a patient’s appetite. In addition stimulant medications increase dopamine which may inhibit growth hormone. This was the explanation offered in the 1970s when studies reported reductions in height in children treated with stimulant medication. But subsequent studies confused both clinicians and families in that the results were mixed; some studies showed a decrease in height and other studies found no significant growth changes. The authors of the more recent landmark study speculate that previous studies looking at the impact of ADHD on adult height and height during adolescence may have been to short in its duration.

The new data presented in the October 2014 Pediatrics adds valuable information. The study was well designed and should reassure families and doctors prescribing stimulant medication that there is no need to be concerned that ADHD patients will not reach their full potential adult height.

A few months ago, in the same publication, researchers at the Bloomberg School of Public Health and the Center for Health Research in Danville, Pennsylvania published another landmark study, looking this time at the impact of stimulant medications on a child’s body mass index (BMI) trajectory. This was the first longitudinal study ever looking at the way ADHD management impacts the BMI. (Pediatrics Vol 133, Number 4)

The data showed that childhood ADHD not treated with stimulants was associated with higher childhood BMIs. In contrast, ADHD treated with stimulants was associated with slower early BMI growth. However when these children were followed, well into their late teens, the researchers noticed a rebound effect on the BMI. The authors commented that their robust research raises the issue of longer-term stimulants playing a role in the development of obesity in later childhood. They conclude by saying that “Our findings should motivate greater attention to the possibility that longer-term stimulant use plays a role in the development of obesity in children”

Given the above data, generated at prestigious institutions such as Harvard, the Mayo Clinic and the John Hopkins School of Public health, where does it leave parents and doctors when important decisions have to be made about the use of stimulants to treat ADHD?
My own opinion may be controversial in that I feel too many children fall through the cracks when they are only seen by doctors. The Canadian Health Care system pays for doctor visits; it does not pay for in-depth psychological assessments. . Not all families are able to afford this care.

Psychological work-ups often reveal additional data related to cognitive skills and co-morbidities. Hours are spent with families which allows for a more accurate diagnosis. Medication alone is not always the best solution. Other treatment modalities such as the Cogmed method, behavioral therapy and parent training should be considered on a case-by-case basis.

Some parents find it astonishing that the two studies described above are the first of its kind. Some families feel that not enough of these studies have been done to reassure them. They remain concerned about how ADHD medications impact a child’s growth.

In the end there is a fine line between the well-described benefits of stimulant medications and their impact on growth. These two recently published landmark studies should remind doctors who track the growth of children with ADHD to remain diligent in addressing lifestyle factors which impact the BMI trajectory.

Meanwhile, it is reassuring that adult height appears to be unaffected. The BMI monitoring of ADHD patients becomes especially important when patients transition their care from pediatricians to family doctors during late adolescence.
For more information on ADHD both in children and adults visit

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