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BACKGROUND: Attention-deficit/hyperactivity-disorder (ADHD) is a leading neurodevelopmental disorder in children worldwide; however, few modifiable risk factors have been identified. Organophosphate esters (OPEs) are ubiquitous chemical compounds that are increasingly prevalent as a replacement for other regulated chemicals. Current research has linked OPEs to neurodevelopmental deficits. The purpose of this study was to assess gestational OPE exposure on clinically-assessed ADHD in children at age 3 years. METHODS: In this nested case-control study within the Norwegian Mother, Father, and Child Cohort study, we evaluated the impact of OPE exposure at 17 weeks gestation on preschool-age ADHD. Between 2007 and 2011, 260 ADHD cases were identified using the Preschool Age Psychiatric Assessment and compared to a birth-year-stratified control group of 549 children. We categorized bis(2-butoxyethyl) phosphate (BBOEP) and bis(1,3-dichloro-2-propyl) phosphate (BDCIPP) as values

This study aimed to evaluate the effectiveness of the International Child Development Programme (ICDP), a group‐based parenting programme used internationally and implemented nationally in Norway. We used a cluster randomized controlled trial in which 81 groups were randomly assigned to either the intervention or waitlist control condition after the baseline data collection. A total of 590 parents completed at least one of three questionnaires (administrated before and after ICDP and 4 months after completing the intervention). Primary outcomes included parental self‐efficacy, parental emotion sensitivity and positive involvement with their child. Secondary outcomes included parents' perceptions of their relationship with the child, child‐rearing conflicts and the child's psychosocial health. We found significant effects favouring the intervention arm following the intervention and at follow‐up on two primary outcomes (parental self‐efficacy and emotion sensitivity). For the secondary outcomes, we found a significant reduction in child‐rearing conflict at the 4‐month follow‐up, increased closeness to the child, reduced child internalizing difficulties and increased prosocial behaviour immediately following the intervention. However, ICDP seems to have limited effects on parent‐reported changes in children. We conclude that ICDP as a universal preventive programme offered to parents in groups can be effective in strengthening parental self‐efficacy and improving parental emotion sensitivity. [ABSTRACT FROM AUTHOR]

Background: The underlying behavioral/psychological processes of attention-deficit/hyperactivity disorder are unclear. Motivational factors, related to dopamine dysfunction, may play an important role in the development of the behavioral symptoms. Particularly, infrequent, but not frequent, reinforcers have been suggested to be associated with altered responding and deviant behavior in children with ADHD. The present study was designed to analyze the influence of reinforcement frequency on operationalized measures of hyperactivity, impulsiveness, sustained attention, and response variability. Methods: Fifty-six boys, half of whom were diagnosed with ADHD, completed a computerized task presented as a game with two squares on the screen. One square was associated with reinforcement. The task required responses by the computer mouse under contingencies alternating between variable interval schedules of short (mean 2 s) and long (mean 20 s) durations. Reinforcers were cartoon pictures and small trinkets. Results: Overall, there was no difference between children with ADHD and comparison children when reinforcers were given frequently. Statistically significant differences on measures of sustained attention and variability, but not hyperactivity and impulsiveness, were found during infrequent reinforcement only. Age effects interacted with group effects on sustained attention, showing that group differences were found in the young children only. Surprisingly, older comparison children showed increased response variability and no learning. Conclusions: When reinforcers are infrequent, children with ADHD show deficient sustained attention and increased variability in responding. Computer experience may have interfered with measures of hyperactivity and impulsiveness. The unexpectedly poor performance of the older comparison children may have been due to inefficient reinforcers or to verbally governed behavior overruling reinforcer effects. Reinforcer characteristics and experimental procedures are important factors influencing findings in studies investigating motivational factors. The study provides some support for the dynamic developmental theory of ADHD predicting relationships between neurobiological deficits, altered reinforcement mechanisms, and treatment recommendations.

Background: Maternal thyroid function plays an important role in foetal brain development; however, little consensus exists regarding the relationship between normal variability in thyroid hormones and common neurodevelopmental disorders, such as attention‐deficit hyperactivity disorder (ADHD). Objective: We sought to examine the association between mid‐pregnancy maternal thyroid function and risk of clinically diagnosed ADHD in offspring. Methods: We conducted a nested case–control study in the Norwegian Mother, Father and Child Cohort Study. Among children born 2003 or later, we randomly sampled singleton ADHD cases obtained through linkage with the Norwegian Patient Registry (n = 298) and 554 controls. Concentrations of maternal triiodothyronine (T3), thyroxine (T4), T3‐Uptake, thyroid‐stimulating hormone (TSH) and thyroid peroxidase antibody (TPO‐Ab) were measured in maternal plasma, collected at approximately 17 weeks' gestation. Indices of free T4 (FT4i) and free T3 (FT3i) were calculated. We used multivariable adjusted logistic regression to calculate odds ratios and accounted for missing covariate data using multiple imputation. We used restricted cubic splines to assess non‐linear trends and provide flexible representations. We examined effect measure modification by dietary iodine and selenium intake. In sensitivity analyses, we excluded women with clinically significant thyroid disorders (n = 73). Results: High maternal T3 was associated with increased risk of ADHD (5th vs 1st quintile odds ratio 2.27, 95% confidence interval 1.21, 4.26). For FT4i, both the lowest and highest quintiles were associated with an approximate 1.6‐fold increase in risk of ADHD, with similar trends found for T4. The FT4i association was modified by dietary iodine intake such that the highest risk strata were confined to the low intake group. Conclusions: Both high and low concentrations of maternal thyroid hormones, although within population reference ranges, increase the risk of ADHD in offspring. Increased susceptibility may be found among women with low dietary intake of iodine and selenium. [ABSTRACT FROM AUTHOR]