A Randomized, Double-Blind, Crossover Comparison of MK-0929 and Placebo in the Treatment of Adults With ADHD

Objective: Preclinical models, receptor localization, and genetic linkage data support the role of D4 receptors in the etiology of ADHD. This proof-of-concept study was designed to evaluate MK-0929, a selective D4 receptor antagonist as treatment for adult ADHD. Method: A randomized, double-blind, placebo-controlled, crossover study was conducted in adults with primary ADHD. The primary end point was changed from baseline in total score on the Adult ADHD Investigator Symptom Rating Scale following a 4-week treatment regimen. Additional measures included Clinical Global Impression-Severity Scale, Hospital Anxiety and Depression Scale, and Brown Attention Deficit Disorder Scale and D4 genotype analysis. Results: No statistically significant treatment differences were found between MK-0929 and placebo in any of the primary or secondary assessments. Conclusion: Results from this study suggest that blockade of the D4 receptor alone is not efficacious in the treatment of adult ADHD.     

Evidence of a transition from perceptual to category induction in 3- to 9-year-old children

We examined whether inductive reasoning development is better characterized by accounts assuming an early category bias versus an early perceptual bias. We trained 264 children aged 3 to 9 years to categorize novel insects using a rule that directly pitted category membership against appearance. This was followed by an induction task with perceptual distractors at different levels of featural similarity. An additional 52 children were given the same training followed by an induction task with alternative stimuli. Categorization performance was consistently high; however, we found a gradual transition from a perceptual bias in our youngest children to a category bias around 6 or 7 years of age. In addition, children of all ages were equally distracted by higher levels of featural similarity. The transition is unlikely to be due to an increased ability to inhibit perceptual distractors. Instead, we argue that the transition is driven by a fundamental change in children's understanding of category membership.     

Motor deficits associated with mild, chronic hyponatremia: a factor analytic study

ABSTRACT Chronic hyponatremia (CHN) has traditionally been considered asymptomatic. If symptoms are observed, they are often mistakenly attributed to the underlying disorder. However, in recent studies neuropsychological deficits have been associated with CHN. The authors sought to determine the association between CHN and motor deficits. They used previously collected data, and 41 subjects with hyponatremia were included. An exploratory factor analysis with principal component analysis (PCA) was performed (eigenvalues >1.0). Factor scores were generated for each subject based on the resultant PCA factor structure. Finally, partial correlations were computed to measure the degree of association between baseline serum sodium concentration [Na+] and individual neuropsychological factor scores with the effect of age removed. All significance tests were performed using 2-tailed comparisons with alpha level of p ≤ .05. A 3-factor model emerged accounting for 70.17% of the total variance, including 1 factor that loaded primarily with motor speed and reaction time. A significant correlation was observed between this motor factor and serum [Na+] (r = -.477, p = .002). These findings add to previous observations suggesting that CHN is associated with subtle yet harmful motor deficits.     

Age, training, and previous experience predict race performance in long-distance inline skaters, not anthropometry

The association of characteristics of anthropometry, training, and previous experience with race time in 84 recreational, long-distance, inline skaters at the longest inline marathon in Europe (111 km), the Inline One-eleven in Switzerland, was investigated to identify predictor variables for performance. Age, duration per training unit, and personal best time were the only three variables related to race time in a multiple regression, while none of the 16 anthropometric variables were related. Anthropometric characteristics seem to be of no importance for a fast race time in a long-distance inline skating race in contrast to training volume and previous experience, when controlled with covariates. Improving performance in a long-distance inline skating race might be related to a high training volume and previous race experience. Also, doing such a race requires a parallel psychological effort, mental stamina, focus, and persistence. This may be reflected in the preparation and training for the event. Future studies should investigate what motivates these athletes to train and compete.     

Sugaring o'er the devil: Moral superiority and group identification help individuals downplay the implications of ingroup rule‐breaking

We examined how a group's claim to moral superiority influences evaluations of rule‐breaking by ingroup members. Moral superiority was manipulated among researchers (Study 1) and British citizens (Study 2), after which group members were presented with ingroup rule‐breakers: a researcher violating ethical rules (Study 1) and British soldiers abusing Iraqi prisoners (Study 2). In both studies, higher and lower identifiers in the control condition perceived the rule‐breaking as equally damaging, evaluated the rule‐breakers equally negatively and recommended equally harsh punishments. When the group had taken the moral high ground, lower identifiers perceived the rule‐breaking as more damaging than did higher identifiers. In addition, higher identifiers evaluated the rule‐breakers less negatively and recommended more lenient punishments. Results of mediation analyses demonstrated that negative evaluations of, and recommended punishment for, the rule‐breakers were explained by the perceived damage that their behaviour caused to the ingroup. Theoretical and practical implications are discussed. Copyright © 2011 John Wiley & Sons, Ltd.     

Priming correct information reduces the misinformation effect

The misinformation effect is a well-established phenomenon in the false memory literature, although the mechanisms that underlie it are debated. In the present study, we explored one aspect of the controversy, the fate of the original memory. We began from an activation-based view of memory, capitalizing on the well-understood processes of associative priming and spreading activation, to test the hypothesis that true and suggested information can coexist in memory. After exposure to misinformation, participants were unknowingly primed with associates of either the true or a suggested item. Misled participants who were primed for the true item performed better on a final memory test than did misled participants primed for neutral information. The results indicated that true and suggested information coexist and that retrieval is influenced by each concept's activation level at test. Implications for theories of the misinformation effect were discussed.     

The role of the amygdala in face perception and evaluation

Faces are one of the most significant social stimuli and the processes underlying face perception are at the intersection of cognition, affect, and motivation. Vision scientists have had a tremendous success of mapping the regions for perceptual analysis of faces in posterior cortex. Based on evidence from (a) single unit recording studies in monkeys and humans; (b) human functional localizer studies; and (c) meta-analyses of neuroimaging studies, I argue that faces automatically evoke responses not only in these regions but also in the amygdala. I also argue that (a) a key property of faces represented in the amygdala is their typicality; and (b) one of the functions of the amygdala is to bias attention to atypical faces, which are associated with higher uncertainty. This framework is consistent with a number of other amygdala findings not involving faces, suggesting a general account for the role of the amygdala in perception.     

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.