The Effects of Childhood ADHD Symptoms on Early-onset Substance Use: A Swedish Twin Study

Research has documented that children and adolescents with attention-deficit/hyperactivity disorder (ADHD) are at increased risk of substance use problems. Few studies, however, have focused on early-onset substance use. This study therefore investigated how the two symptom dimensions of ADHD (hyperactivity/impulsivity and inattention) are associated with early-onset substance use, the role of persistent ADHD for the association, and to what extent the association is influenced by genetic and environmental factors. Twins (1,480 pairs) in the Swedish Twin Study of Child and Adolescent Development were followed from childhood to adolescence. ADHD symptoms were measured at age 8–9 and age 13–14 via parent-report, whereas substance use was assessed at age 13–14 via self-report. Results revealed that hyperactive/impulsive symptoms predicted early-onset “sometimes” tobacco use (adjusted odds ratios, 1.12, for one symptom count), controlling for inattentive symptoms and conduct problem behaviors. There is no independent effect of inattentive symptoms on early-onset substance use. Children with persistent hyperactivity/impulsivity (defined as scoring above the 75th percentile at both time points) had a pronounced risk of both early-onset tobacco and alcohol use (adjusted odds ratios from 1.86 to 3.35, compared to the reference group). The associations between hyperactivity/impulsivity and early-onset substance use were primarily influenced by genetic factors. Our results indicated that hyperactivity/impulsivity, but not inattention, is an important early predictor for early-onset substance use, and a shared genetic susceptibility is suggested to explain this association.     

Predictors of Boys’ ADHD Symptoms from Early to Middle Childhood: The Role of Father–Child and Mother–Child Interactions

This prospective 3 year longitudinal study investigated preschool paternal and maternal parenting predictors of Attention-Deficit/Hyperactivity Disorder(ADHD) in a community sample of 93 school-age boys. Participants were recruited on the basis of inattention-hyperactivity at age 4 and fathers and mothers were observed interacting with their sons. Teachers, fathers, and mothers reported children's ADHD symptoms and impairment. Results from dimensional analysis showed that less observed paternal sensitivity and maternal positive regard predicted higher levels of inattentiveness in middle childhood, and that intrusive paternal behavior was predictive of hyperactive-impulsive behavior at school. In categorical analysis, less maternal warmth and sensitivity were predictive of later ADHD. These predictions held after statistical adjustment for the effects of preschool ADHD behaviors and conduct problems. At follow-up, parents of boys with ADHD reported more negative child-parent relationship perceptions than comparison parents. Findings highlight the importance of examining responsive parenting behaviors of both fathers and mothers in relation to multi-informant ratings of ADHD symptoms.     

Cross-sectional age differences in personality: Evidence from nationally representative samples from Switzerland and the United States

Identifying reliable patterns of age differences in personality can help clarify the nature of adult personality development. Previous studies have been limited because many have relied on convenience samples. In this study, we examined age differences in personality in two nationally representative samples, one from Switzerland and one from the United States. The results indicated that Agreeableness and Conscientiousness were positively associated with age, whereas Extraversion was negatively associated with age. However, the magnitude of age differences for Extraversion was much smaller than for Agreeableness and Conscientiousness. Openness showed a more complex trend such that 30- to 34-year-olds scored lower on Openness than younger age groups, whereas older groups scored somewhere in between. Inconsistent age differences were observed for Neuroticism.     

Movement control in older adults: does old age mean middle of the road?

Old age is associated with poorer movement skill, as indexed by reduced speed and accuracy. Nevertheless, reductions in speed and accuracy can also reflect compensation as well as deficit. We used a manual tracing and a driving task to identify generalized spatial and temporal compensations and deficits associated with old age. In Experiment 1, participants used a hand-held stylus to trace a path. In Experiment 2, participants steered along paths in a virtual reality driving simulator. In both experiments, participants were required to stay within the boundaries while we manipulated task difficulty by changing path width or movement speed. The older group showed worse performance in the highly constrained conditions. Corner cutting effectively reduces the curvature of bends but yields a greater risk of error (i.e., clipping the path or road edge). Corner cutting is thus less risky on wider paths, and we found that corner cutting increased for both age groups in both tasks when paths were wider. Crucially, we observed a greater degree of corner cutting in the young group compared with the old, suggesting the old group compensated for decreased motor skill with "middle-of-the-road" behavior. Enforcing increased speed caused all participants to increase corner cutting. Thus, older participants showed spatial compensation for decreased skill by biasing their position toward the middle of the path in both a manual and steering task. External constraints (narrow paths and fast speeds) prevented this strategy and revealed age-related declines in skills central to manual control and driving.     

Dysregulated negative emotional reactivity as a predictor of chronic peer victimization in childhood

This study examined the relations of dysregulated negative emotional reactivity, emotional distress, and chronic peer victimization in childhood. A model was proposed whereby dysregulated reactivity was directly and indirectly related to concurrent peer victimization through victimization‐related emotional distress. The model further proposed that dysregulated reactivity directly incrementally predicted longitudinal peer victimization above and beyond the effect of concurrent victimization. Two hundred thirteen 9‐ to 13‐year‐old children and their parents completed measures of dysregulated reactivity and victimization experiences at baseline and 6‐month follow‐up. Children also related narratives of personal victimization experiences at baseline that were coded to assess victimization‐related emotional distress. Model testing strongly supported the direct association of dysregulated reactivity with concurrent victimization and incremental predictive effects of dysregulated reactivity on peer victimization over time. Model testing also provided support for an indirect effect of dysregulated reactivity on concurrent peer victimization through victimization‐related emotional distress. This study demonstrated the powerful role that dysregulated negative emotional reactivity plays in the development of chronic peer victimization over time. Aggr. Behav. 38:414‐427, 2012. © 2012 Wiley Periodicals, Inc.     

A critical evaluation of c as a measure of mnemonic resolution

It is known that visual working memory capacity is limited, but the nature of this limit remains a subject of controversy. Increasingly, two factors are thought to limit visual memory: an object-based limit associated with so-called "slots" models, and an information-based limit associated with resource models. Recently, Barton, Ester, and Awh (2009) introduced a measure of mnemonic resolution, which they dubbed c. We show here that c is critically flawed, and cannot be interpreted as a measure of resolution. We recommend strongly against its use and interpretation, and suggest alternatives approaches for researchers who want to explore mnemonic resolution.     

Mood-congruent thoughts and personality disorder pathology

The primary aim of this research was to investigate associations that depression severity and trait anxiety have with reactions to specific, identifiable thoughts experienced by persons with varying levels of personality disorder (PD) pathology as they went about their day-to-day lives. Ninety-eight psychotropic medication-free persons participated in an experience sampling assessment procedure over four consecutive days, during which participants recorded specific thoughts experienced moments before a page signal was received and corresponding ratings of thought discomfort. Thought discomfort, regarded as an emotional reaction to thoughts or their evaluation, was moderately associated with several forms of PD pathology, particularly Cluster C pathology. Once depression severity and trait anxiety were controlled, however, associations between PD pathology and thought discomfort were eliminated. Findings from this research generally support the mood-congruence of negatively valenced thoughts in relation to PD pathology.     

One hand, two objects: emergence of affordance in contexts

Studies on affordances typically focus on single objects. We investigated whether affordances are modulated by the context, defined by the relation between two objects and a hand. Participants were presented with pictures displaying two manipulable objects linked by a functional (knife-butter), a spatial (knife-coffee mug), or by no relation. They responded by pressing a key whether the objects were related or not. To determine if observing other's actions and understanding their goals would facilitate judgments, a hand was: (a) displayed near the objects; (b) grasping an object to use it; (c) grasping an object to manipulate/move it; (d) no hand was displayed. RTs were faster when objects were functionally rather than spatially related. Manipulation postures were the slowest in the functional context and functional postures were inhibited in the spatial context, probably due to mismatch between the inferred goal and the context. The absence of this interaction with foot responses instead of hands in Experiment 2 suggests that effects are due to motor simulation rather than to associations between context and hand-postures.