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Summary of key findings

Evaluating the Hyperactivity/Inattention Subscale of the National Longitudinal Survey of Children and Youth

This study evaluates the strength of the association between scores on the Hyperactivity/Inattention Subscale of the National Longitudinal Survey of Children and Youth (NLSCY) and each of three potential criteria for Attention Deficit Hyperactivity Disorder (ADHD):  current methylphenidate use, diagnosis of an emotional disorder, and functional impairment.  It also identifies the criterion with the strongest association, adjusting for age, sex and socio-economic status.  

Data from the 1994/1995 NLSCY are used because this cycle of the survey has the most complete information.

The Hyperactivity/Inattention Subscale consists of 8 items (can’t sit still, distractible, fidgets, impulsive, difficulty sitting still, cannot settle for long, can’t concentrate, inattentive) scored as 0 (not true), 1 (sometimes true) or 2 (often true), resulting in a continuous scale with scores from 0 to 16.

Based on a threshold score of 14 or more on the Subscale, an estimated 2.1% of Canadian children aged 6 to 11 had clinically significant ADHD symptoms.

The study demonstrates that scores on the Subscale were associated with two clinical indicators of ADHD in Canadian children aged 6 to 11 in 1994/1995: methylphenidate use (adjusted for age and sex) and previous diagnosis of emotional disorder (adjusted for age and household income).  

Although there is no clear statistical advantage to choosing either current methylphenidate use or previous diagnosis of emotional disorder as the criterion for evaluating the Subscale, there may be broad conceptual value in choosing the latter. While it is no surprise that methylphenidate use can be a criterion for ADHD, it is somewhat more novel that a history of emotional disorder can be used as a criterion as well.

With the method described in this paper, the parent-reported Subscale can be used to identify clinically significant ADHD symptoms in Canadian children aged 6 to 11, either as an outcome measure for investigating developmental antecedents of such symptoms, or as an independent variable predicting adolescent and adult outcomes in the NLSCY sample.

Full article

For more information about this article, contact Alice Charach (1-416-813-6600; alice.charach@sickkids.ca), Faculty of Medicine, University of Toronto, Toronto, Ontario.