Psychometric properties of a French version of the junior temperament and character inventory

The junior temperament and character inventory (JTCI) has been developed for the assessment of temperament and character dimensions in childhood based on Cloninger's model of personality. We evaluated the psychometric proprieties of a French child and parent-rated version of the JTCI based on a previous German version, and assessed the correlations between the JTCI dimension scores and the scores on the child behavior checklist (CBCL) in a community sample of French children and adolescents aged 10-16 years. We used data from 452 child-rated and 233 -parent-rated JCTI. The psychometric properties (internal consistency and external validity in relation to the emotionality activity sociability (EAS) questionnaire) of the French JTCI were adequate in the parent-rated version. The parent-rated JTCI had overall better psychometric qualities than the child-rated version, but for both versions of the JTCI the confirmatory factor analysis showed low fit between the observed data and the original model. Dimensions of the EAS model were significantly correlated with the temperament scales of the JTCI. Further studies are required to improve the psychometric properties of the child-rated JTCI, and to provide insight about lacking fit of our data with the theoretical model.

Lack of association of the dopamine transporter gene in a French ADHD sample

Discrepancies in the role of the 40 bp VNTR polymorphism of the dopamine transporter gene (DAT1) in attention-deficit hyperactivity disorder (ADHD) could be due to various sources of genetic or phenotypical heterogeneity. We therefore analyzed a sample of 146 ADHD children and their parents, with a transmission disequilibrium test (TDT) design, assessing age, inattention, and hyperactivity dimensions and total score of the ADHD Rating Scale, the number of errors and the total score at Stroop Color-Word test, and the total score at the Trail Making Test. The TDT for 10-repeat (10-R) allele shows a perfect lack of transmission bias (Mc Nemar chi(2) = 0) and PBAT analyses showed no role of this polymorphism for any of the studied endophenotypes. Lack of statistical power is always a possibility, but with a sample size above the average of the majority of previous studies, and an odds ratio (number of transmitted versus untransmitted 10-R allele) of 1.00 exactly, this possibility may be considered as not very likely.

Pharmacogenetics of methylphenidate response in attention deficit/hyperactivity disorder: association with the dopamine transporter gene (SLC6A3)

Pharmacogenetic studies investigating the 40-bp VNTR polymorphism at SLC6A3 and methylphenidate response have shown conflicting results and large differences in study design and efficacy endpoints. Our objective was to investigate the relation between the 3'-VNTR at SLC6A3 and variability in methylphenidate response in a sample of 141 ADHD children and adolescents, assessed before and after methylphenidate treatment with both clinical and neuropsychological outcome measures. 10-R homozygotes were significantly overrepresented in the low response group, but no genotype effect was shown in cognitive variables improvement. A meta-analysis of pharmacogenetic studies with comparable data (responders vs. non-responders) on a total of 475 subjects showed a significant association between the 10-10 genotype and low rates of methylphenidate response (mean Odds Ratio = 0.46; 95% CI [0.28-0.76]). Heterogeneity between these studies did not reach a significant level but, as publications with different endpoints were excluded from this meta-analysis, our results do not rule out a possible influence of study design.