Repetitive negative thinking and depressive symptoms are differentially related to response inhibition: The influence of non-emotional, socio-emotional, and self-referential stimuli.

Identifying transdiagnostic correlates of response inhibition deficits is important for understanding risk for internalizing disorders. Little work has compared the relationships between internalizing symptoms and repetitive negative thinking (RNT) with response inhibition across non-emotional and emotional domains, and no work has compared these relationships for inhibition of socio-emotional relative to self-referential stimuli. Undergraduate students (N = 71, 18.44 ± 0.71 years) selected on extremes of internalizing symptoms completed the Perseverative Thinking Questionnaire (PTQ) and a Go/No-Go paradigm using non-emotional stimuli, other individuals' sad facial expressions, and participants' own sad facial expressions. Participants exhibited more commission errors for sad facial expressions than non-emotional trials, though commission errors for others' and participants' own sad facial expressions did not differ. Depressive symptoms were associated with poorer inhibition of non-emotional stimuli; however, PTQ scores were associated with more successful inhibition of non-emotional stimuli. Our results provide evidence that transdiagnostic RNT as assessed by the PTQ may be related to better inhibition in non-emotional domains, but negative emotional stimuli may interfere with successful inhibition for those with high RNT, while depressive symptoms were linked to poorer inhibition of non-emotional stimuli. These findings have implications for internalizing disorders, which often are accompanied by RNT.

Brain Imaging of the Cortex in ADHD: A Coordinated Analysis of Large-Scale Clinical and Population-Based Samples.

OBJECTIVE: Neuroimaging studies show structural alterations of various brain regions in children and adults with attention deficit hyperactivity disorder (ADHD), although nonreplications are frequent. The authors sought to identify cortical characteristics related to ADHD using large-scale studies. METHODS: Cortical thickness and surface area (based on the Desikan-Killiany atlas) were compared between case subjects with ADHD (N=2,246) and control subjects (N=1,934) for children, adolescents, and adults separately in ENIGMA-ADHD, a consortium of 36 centers. To assess familial effects on cortical measures, case subjects, unaffected siblings, and control subjects in the NeuroIMAGE study (N=506) were compared. Associations of the attention scale from the Child Behavior Checklist with cortical measures were determined in a pediatric population sample (Generation-R, N=2,707). RESULTS: In the ENIGMA-ADHD sample, lower surface area values were found in children with ADHD, mainly in frontal, cingulate, and temporal regions; the largest significant effect was for total surface area (Cohen's d=-0.21). Fusiform gyrus and temporal pole cortical thickness was also lower in children with ADHD. Neither surface area nor thickness differences were found in the adolescent or adult groups. Familial effects were seen for surface area in several regions. In an overlapping set of regions, surface area, but not thickness, was associated with attention problems in the Generation-R sample. CONCLUSIONS: Subtle differences in cortical surface area are widespread in children but not adolescents and adults with ADHD, confirming involvement of the frontal cortex and highlighting regions deserving further attention. Notably, the alterations behave like endophenotypes in families and are linked to ADHD symptoms in the population, extending evidence that ADHD behaves as a continuous trait in the population. Future longitudinal studies should clarify individual lifespan trajectories that lead to nonsignificant findings in adolescent and adult groups despite the presence of an ADHD diagnosis.