Impact of anxiety disorders on attentional functions in children with ADHD

Introduction: The impact of internalizing comorbid disorders on cognitive functions in attention-deficit hyperactivity disorder (ADHD) is hardly understood. While inconsistent findings exist with respect to the modulating effect of anxiety on impulsivity in ADHD, only few neuropsychological studies focused on other attention parameters. This is the first study that examines the influence of anxiety disorders (ANX) on ADHD in a model-oriented approach including selectivity and intensity parameters of attention. Methods: Children with ADHD, ADHD + ANX and healthy controls (n = 34 for each group, all aged 8-15 years) participated in five neuropsychological tasks (alertness, sustained attention, divided attention, go/no-go and set-shifting). Group differences were evaluated using analysis of variance (ANOVA) for each dependent variable, with group as independent variable. Results: Data indicated that children with ADHD performed worse than healthy controls with regard to almost all parameters of attention. While ANX had no mitigating effect on impulsivity in ADHD, performance in sustained attention and selective attention tasks of children with ADHD + ANX was better than that of children with ADHD only. Limitations: Since the present data were derived from a large neuropsychological data base which focused primary on children with ADHD and different comorbidities no comparison to a "pure" ANX group was possible. Conclusions: These findings might indicate that ADHD + ANX constitute a cognitively distinct subtype, with possible individual symptomatology, development and therapeutic needs. Further investigations are needed to clarify the specificity of these findings and to disentangle the impact of trait versus state anxiety on neuropsychological performance in children with ADHD. (C) 2009 Elsevier B.V. All rights reserved.