Bone Health, Attention-deficit Hyperactivity Disorder, and the Role of Psychostimulant Abuse: A Reply to Howard et al (2015)
Howard et al1 conducted a population-based study using the National Health and Nutrition Examination Survey (NHANES) database to clarify the relationship between use of attention-deficit hyperactivity disorder (ADHD) medications and bone mineral density (BMD) in children. The authors found significantly lower BMD about the femoral neck, total femur, and lumbar spine in medicated children, suggesting that the use of ADHD medications in children may harbor deleterious effects on bone health during critical periods of growth. However, the study design did not capture whether the medicated participants were actually diagnosed with the disorder from a psychiatric evaluation. As abuse of ADHD medications among adolescents is an increasing trend,2 the findings on the association between medications used to manage ADHD and BMD should not be taken to infer deleterious bone health in ADHD generally, and this distinction was not clearly stated in the work by Howard et al.1 Previous findings cited by Howard et al1 indicate that long-term use of methylphenidate among children diagnosed with ADHD did not result in any significant difference in BMD compared with healthy controls,3 suggesting that, if methylphenidate use is associated with lower BMD, BMD in medication-naive ADHD may be elevated compared with controls, and this has been observed previously.4 Therefore, any association between ADHD medication use in children and BMD may carry more clinical importance to non-ADHD abusers of these medications than to ADHD subjects themselves. However, this critical distinction was curiously absent in the work by Howard et al.1
Although the study design and use of public databases may have enabled Howard et al1 to accrue a substantial sample size, there was a critical loss of ADHD discernment in the population. Given the evidence of increasing abuse of ADHD medications among non-ADHD subjects, it is quite probable that Howard et al1 have captured a large cohort of non-ADHD adolescents abusing these medications. The authors should include this limitation in their study design so as not to unnecessarily worry parents of children with ADHD who may find pause, given the findings of Howard et al,1 in their child’s use of medications to manage a diagnosed disorder. Therefore, a significant limitation of the work that should be explicitly noted is that deleterious bone health effects may arise from possible abuse and/or overmedication of children without the certitude of an ADHD diagnosis.