Longitudinal Prediction of the One-Year Course of Preschool ADHD Symptoms: Implications for Models of Temperament-ADHD Associations.

Despite the fact that Attention-Deficit/Hyperactivity Disorder (ADHD) is often conceptualized as an extreme trait, there remains controversy about the best way to understand associations between temperament traits and ADHD. The current study examines longitudinal associations between temperament traits and ADHD during early childhood in order to critically examine vulnerability and spectrum models of trait-ADHD associations. Study participants were 109 children between the ages of 3 and 6 and their primary caregivers and teachers/daycare providers, community-recruited for ADHD-related problems. Primary caregivers completed the Kiddie Disruptive Behavior Disorders Schedule semi-structured diagnostic interview at the initial appointment and one year later. At the initial appointment, primary caregivers completed the Child Behavior Questionnaire as a measure of child temperament traits. Results from the initial time point indicated that high neuroticism and high surgency were associated with inattentive and hyperactive-impulsive ADHD symptoms, and low effortful control was associated with hyperactive-impulsive ADHD symptoms. However, none of these traits predicted the one-year course of ADHD symptoms. Results are more consistent with a spectrum (vs. vulnerability) model of trait-psychopathology associations, suggesting that traits, but may not influence longitudinal course during early childhood.

Prenatal Testosterone and Preschool Disruptive Behavior Disorders.

Disruptive Behaviors Disorders (DBD), including Oppositional-Defiant Disorder (ODD) and Attention-Deficit/Hyperactivity Disorder (ADHD), are fairly common and highly impairing childhood behavior disorders that can be diagnosed as early as preschool. Prenatal exposure to testosterone may be particularly relevant to these early-emerging DBDs that exhibit a sex-biased prevalence rate favoring males. The current study examined associations between preschool DBD symptom domains and prenatal exposure to testosterone measured indirectly via right 2D:4D finger-length ratios. The study sample consisted of 109 preschool-age children between ages 3 and 6 (64% males;72% with DBD) and their primary caregivers. Primary caregivers completed a semi-structured interview (i.e., Kiddie Disruptive Behavior Disorder Schedule), as well as symptom questionnaires (i.e., Disruptive Behavior Rating Scale, Peer Conflict Scale); teachers and/or daycare providers completed symptom questionnaires and children provided measures of prenatal testosterone exposure, measured indirectly via finger-length ratios (i.e., right 2D:4D). Study results indicated a significant association of high prenatal testosterone (i.e., smaller right 2D:4D) with high hyperactive-impulsive ADHD symptoms in girls but not boys, suggesting that the effect may be driven by, or might only exist in, girls. The present study suggests that prenatal exposure to testosterone may increase risk for early ADHD, particularly hyperactivity-impulsivity, in preschool girls.

Are There Executive Dysfunction Subtypes Within ADHD?

OBJECTIVE: Children with ADHD have heterogeneous behavioral and neuropsychological profiles. The aim of this study was to examine the possible utility of executive function (EF) subtypes within ADHD. METHOD: Participants were 357 children aged 6 through 13 with a diagnosis of ADHD. Children completed a brief laboratory battery measuring EF, including response inhibition, response variability, speed, and set-shifting. Children also completed standardized intelligence and achievement testing. RESULTS: Two-way cluster analysis of EF profiles of children with ADHD produced a three-cluster solution, labeled poor inhibitory control, poor set-shifting/speed, and intact task performance. Clusters significantly differed in measures of intelligence, academic achievement, and other disruptive behavior and anxiety/mood symptoms. CONCLUSION: These findings further support the idea that children with ADHD have heterogeneous EF profiles and suggest that the theory of ADHD should consider these individual differences in EF profiles within the ADHD diagnostic category.

Prenatal testosterone increases sensitivity to prenatal stressors in males with disruptive behavior disorders.

Disruptive Behavior Disorders (DBD) exhibit a sex-biased prevalence rate favoring boys, and prenatal testosterone exposure appears to be part of the complex etiology of these disorders. The current study examines whether high prenatal testosterone exposure may heighten the risk for DBD symptoms in males by increasing susceptibility to negative environmental conditions such as maternal nicotine and alcohol use during pregnancy. Participants were 109 three- to six-year-olds (64% male; 72% with DBD) and their 109 primary caregivers and 55 daycare providers/teachers who completed a multi-informant diagnostic procedure. A proxy of prenatal testosterone exposure, finger-length ratios, interacted with maternal report of prenatal nicotine use to predict teacher-rated hyperactivity-impulsivity during preschool, for boys, but not girls, although the three-way interaction was not significant. Prenatal testosterone interacted with prenatal alcohol exposure to predict teacher-rated hyperactivity-impulsivity and ODD symptoms differentially based on child sex (significant three-way interaction). Boys with higher levels of prenatal testosterone who were also exposed to higher levels of nicotine and alcohol during pregnancy exhibited increased hyperactivity-impulsivity during early childhood, but girls did not exhibit this same pattern. Thus, high prenatal testosterone exposure seems to increase risk for DBD symptoms particularly in males by increasing susceptibility to prenatal environmental stressors.