MOTHER NATURE AS TREATMENT FOR ADHD: OVERSTATING THE BENEFITS OF GREEN

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In the September issue of the Journal, Kuo and Faber Taylor1 suggest that activities in green (i.e., natural) surroundings are “widely effective” in reducing symptoms associated with attention-deficit/hyperactivity disorder (ADHD). However, because this Internet-based study is rife with methodological limitations, it does not offer convincing scientific evidence of this treatment’s effectiveness. For example, participants were designated as having ADHD not on the basis of research criteria but on the basis of parental reports of a professional diagnosis. Given long-appreciated inconsistencies in how care-givers in the community evaluate children for ADHD,2,3 the sample must have been highly heterogeneous in symptom presentation and impairment level. Because the study did not include any healthy controls or controls with psychiatric illnesses, it is entirely unclear whether the “green effects” addressed ADHD-type impairments any more than they would have enhanced attention across other groups. It is also cause for concern that the survey asked parents to rate primarily inattentive behaviors associated with ADHD, neglecting equally prevalent (and generally more impairing) impulsive/hyperactive symptoms. Even if the treatment effects were legitimate, they would be narrow in scope. Furthermore, the authors’ claim that natural surroundings reduce ADHD symptoms is based solely on global, retrospective impressions, not on direct observations of how children behaved following activities held constant except for the setting. The article does not specify the exact nature of each activity, why parental recollections should be considered accurate, or whether any effects lasted longer than an hour after the green dose. Kuo and Faber Taylor draw their conclusions on the basis of statistical significance, not actual clinical impact. For instance, the largest mean “aftereffects” difference between green outdoor activities and indoor activities was 4.34 (apparently on a 40-point scale), suggesting a fairly modest effect for environmental setting. Finally, the authors frequently cite unpublished data as corroborating their conclusions. Such data hold little sway because they have not been peer reviewed. While the pursuit of effective nonmedical interventions for ADHD is certainly noble, we worry when unproven ideas are presented as if they were well-established treatments. That the authors imply that exposure to green surroundings may be the only alternative to medication for some children also bothers us. This conclusion ignores an extensive literature on psychosocial treatments that includes parent training programs and classroom management techniques.4 As it stands, these other programs currently enjoy far more scientific rigor than programs involving a walk in the park.