Methylphenidate use and divorce
===============================

* Brandon K. Schultz, EdS NCSP

*   © 2007 Canadian Medical Association or its licensors

The findings in a *CMAJ* research article by Lisa Strohschein on methylphenidate use among Canadian children are likely to be misinterpreted because of the methodology used and the author's interpretation of the data.1 Strohschein used survey data indicating whether divorce occurred in participating Canadian households at any point from 1994 to 2000 to categorize families as those in which the parents remained married and those in which the parents divorced; similarly, methylphenidate use was considered to have been present if a parent reported that their child used the drug at any point from 1994 to 2000.1 Rather than assessing the prevalence of methylphenidate use among Canadian children following parental divorce, as suggested by the article's title, it appears that the analysis simply uncovers unusually high rates of methylphenidate use before, during or after divorce, a finding that is not that surprising given evidence for a genetic basis for attention- deficit hyperactivity disorder2 and clear associations between this disorder and parental strain.3,4

Further confusion is created by the use of the word “subsequent[ly]” several times in the article. For example, the author claims in the interpretation section that “... divorce itself is a predictor of subsequent methylphenidate use”; however, the predictor (divorce) and outcome (methylphenidate use) variables did not necessarily occur sequentially. Although the author takes great care to offer alternative explanations for her findings, one can easily imagine how this article could be widely misinterpreted.

In short, this article seems to presume a sequence of events that the analysis does not support. To avoid misinterpretation, readers should be strongly discouraged from assuming that divorce precedes or causes increased methylphenidate use, on the basis of these data alone.

## Footnotes

*   **Competing interests:** None declared.

## REFERENCES

1.  1. Strohschein LA. Prevalence of methylphenidate use among Canadian children following parental divorce. CMAJ 2007;176:1711-4.
    
    [Abstract/FREE Full Text](http://www.cmaj.ca/lookup/ijlink/YTozOntzOjQ6InBhdGgiO3M6MTQ6Ii9sb29rdXAvaWpsaW5rIjtzOjU6InF1ZXJ5IjthOjQ6e3M6ODoibGlua1R5cGUiO3M6NDoiQUJTVCI7czoxMToiam91cm5hbENvZGUiO3M6NDoiY21haiI7czo1OiJyZXNpZCI7czoxMToiMTc2LzEyLzE3MTEiO3M6NDoiYXRvbSI7czoyMjoiL2NtYWovMTc3LzcvNzUxLjEuYXRvbSI7fXM6ODoiZnJhZ21lbnQiO3M6MDoiIjt9) 

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