Hoffman, L. (2009). Treating Childhood Anxiety. N Engl J Med 360:2475, June 4, 2009 Correspondence
To the Editor: In the editorial accompanying the report by Walkup et al., Emslie1 states, in support of randomized, controlled trials, “It appears unlikely that the majority of children with severe and persistent anxiety disorders are receiving optimal evidence-based care in the community.” I do not believe that the results reported by Walkup et al. can be generalized, in that 84% of potential subjects were excluded (3066 screened, and 488 randomly assigned to a study group), making the external validity2 of the findings doubtful.
The internal validity2 is uncertain because there was no control for factors that contribute to the development of psychiatric disturbances in children. Although the authors control for demographic factors, diagnoses, and racial or ethnic diversity (not “the most socioeco nomically disadvantaged”), there is no report of family history (marital discord, deaths, separations, or maltreatment of children by family members or others), nor is there information about the children’s developmental and psychological trajectories.
This study, like others,3 may do a disservice to the care of children by conceptualizing pediatric psychiatric disorders as if they were categorical entities. Proper treatment can be implemented only when the full complexity of such disorders is understood, including developmental and family factors.4
Leon Hoffman, M.D.
New York Psychoanalytic Institute
New York, NY 10028
hoffman.leon@gmail.com
1. Emslie GJ. Pediatric anxiety — underrecognized and undertreated. N Engl J Med 2008;359:2835-6.
2. Kazdin AE. Introduction and drawing valid inferences: internal and external validity. In: Kazdin AE. Research design in clinical psychology. 4th ed. Needham Heights, MA: Allyn & Bacon, 2003:1-54.
3. Bridge JA, Birmaher B, Iyengar S, Barbe RP, Brent DA. Placebo response in randomized controlled trials of antidepressants for pediatric major depressive disorder. Am J Psychiatry 2009;166:42-9.
4. Pynoos RS, Steinberg AM, Piacentini JC. A developmental psychopathology model of childhood traumatic stress and intersection with anxiety disorders. Biol Psychiatry 1999;46:1542-54.
Reply by authors to Hoffman letter
……In response to Hoffman: the number of willing and eligible participants was 524, and of that group, 488 underwent randomization. The study results are generalizable to populations of anxious children who have clinical characteristics that are similar to those of the study sample. We believe that the demonstrated success of randomization probably controls for the distribution of factors not assessed.
That said, a number of the factors mentioned by Hoffman were assessed, and we are evaluating the moderating effects of these factors on outcomes. ……..
John T. Walkup, M.D.