Anxiety as a predictor and outcome variable in the Multimodal Treatment Study of Children with ADHD (MTA)

Initial moderator analyses in the Multimodal Treatment Study of Children wi th ADHD (MTA) suggested that child anxiety ascertained by parent report on the Diagnostic Interview Schedule for Children 2.3 (DISC Anxiety) different ially moderated the outcome of treatment. Left unanswered were questions re garding the nature of DISC Anxiety, the impact of comorbid conduct problems on the moderating effect of DISC Anxiety, and the clinical significance of DISC Anxiety as a moderator of treatment outcome. Thirty-three percent of MTA subjects met DSM-III-R criteria for an anxiety disorder excluding simpl e phobias. Of these, two-thirds also met DSM-III-R criteria for comorbid op positional-defiant or conduct disorder whereas one-third did not, yielding an odds ratio of approximately two for DISC Anxiety, given conduct problems . In this context, exploratory analyses of baseline data suggest that DISC Anxiety may reflect parental attributions regarding child negative affectiv ity and associated behavior problems (unlike fearfulness), particularly in the area of social interactions, another core component of anxiety that is more typically associated with phobic symptoms. Analyses using hierarchical linear modeling (HLM) indicate that the moderating effect of DISC Anxiety continues to favor the inclusion of psychosocial treatment for anxious ADHD children irrespective of the presence or absence of comorbid conduct probl ems. This effect, which is clinically meaningful, is confined primarily to parent-reported outcomes involving disruptive behavior, internalizing sympt oms, and inattention: and is generally stronger for combined than unimodal treatment. Contravening earlier studies, no adverse effect of anxiety on me dication response for core ADHD or other outcomes in anxious or nonanxious ADHD children was demonstrated. When treating ADHD, it is important to sear ch for comorbid anxiety and negative affectivity and to adjust treatment st rategies accordingly.