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The article presents a study that investigates the prospective stability predictors of the subtypes of attention-deficit/hyperactivity disorder (ADHD) in American children and teenager. The study of the population-based and Diagnostic and Statistical Manual of Mental Disorders (DSM-IV) predictor was administered to 708 twin participants whose age ranges from seven to 19 years. The predictors of the subtypes of ADHD were evaluated using multivariate logistic regression and reassessed after five years through a blinded fashion method and the significance of agreement percentage. It reveals that population-based ADHD subtype manifests an improvement after five years compared from DSM-IV, however, there are no existing factor that asserts the predictor of stability in both subtypes.

Focuses on a study which examined the difference between two attention-deficit hyperactivity disorder (ADHD) subtyping approaches to the prediction of cognitive function and educational achievement of child and adolescent twins in Missouri. Background on DSM-IV ADHD subtypes; Details of diagnostic assessment; Characteristics of samples; Results of cognitive and educational achievement scores; Discussion on school performance reports.

Examines the genetic structure of deficits in reciprocal social behavior in male twins in Missouri. Comparison between monozygotic and dizygotic twins in the Social Reciprocity Scale; Incorporation of genetic and environmental influences in social behavior; Importance of social behavior for autism phenotype characterization.

The article presents a study in the U.S., which is aimed to determine treatment patterns for youth attention-deficit/hyperactivity disorder (ADHD) symptoms in a general population sample of 1,610 twins. The researchers interviewed the twins using the Missouri Assessment of Genetics Interview for Children. It was found out that earlier studies of the same matter were undertreated. Recent results indicate that complex factors, including comorbid disorders and family history of ADHD treatment, affect treatment patters in general populations.

Background: It has been proposed that some of the variability in reporting of associations between attention deficit hyperactivity disorder (ADHD) and candidate genes may result from mixing of genetically heterogeneous forms of ADHD using DSM-IV criteria. The goal of the current study is to test whether population-based ADHD subtypes defined by latent class analysis help resolve issues of variable findings across individual gene association studies., Methods: Three studies which had previously reported no associations between polymorphisms of the DRD4 and DAT genes and DSM-IV defined ADHD were reanalyzed using population-based and DSM-IV defined ADHD subtypes., Results: Across studies no significant associations were found for either DRD4 or DAT polymorphisms using DSM-IV ADHD subtypes. In contrast, a significant association was found between the combined data set for the 440 base pair 3' DAT VNTR polymorphism and population-defined severe combined ADHD (OR=1.25, p=.01). A marginally significant association was also found between the 7 repeat DRD4 allele and population-defined severe combined ADHD., Conclusion: Use of alternative population-based defined ADHD subtypes may help resolve some of the variable results presented for candidate gene association studies in ADHD.

Context: We have reported elsewhere on the development of an 8-item Obsessive-Compulsive Scale (OCS) contained in the Child Behavior Checklist (CBCL) to identify children who meet criteria for DSM-IV obsessive-compulsive disorder. Twin studies of obsessive-compulsive disorder have indicated a significant genetic component to its expression., Objective: To determine the relative contributions of genetic and environmental influences on childhood obsessive-compulsive behavior using the CBCL OCS in twin samples., Design: The CBCL data were received by survey of twins in the Netherlands Twin Registry (NTR) and the Missouri Twin Study (USA/MOTWIN)., Setting: General community twin samples., Participants: Participants were 4246 twin pairs aged 7 years, 2841 aged 10 years, and 1562 aged 12 years (who also participated in the study at 7 and 10 years of age) from the NTR and 1461 mixed-age twin pairs (average age, approximately 9 years) from the USA/MOTWIN., Main Outcome Measures: Model fitting to test for genetic and environmental influences, sex differences, and sibling interaction/rater contrast effects on the CBCL OCS., Results: In each case, the best-fitting model was one that indicated significant additive genetic influences (range, 45%-58%; 95% confidence interval [CI], 45%-61%), and unique environmental influences (range, 42%-55%; 95% CI, 39%-55%), with shared environmental influences in the NTR sample aged 12 years (16%). Sex differences were seen in the mixed-age USA/MOTWIN model, but not in the NTR samples. No evidence of dominance, sibling interaction, or rater-contrast effects was seen. These data were relatively consistent across age and cultures., Conclusions: The CBCL OCS is influenced by genetic factors (approximately 55%) and unique environmental factors (approximately 45%) in the younger sample, with common environmental influences only at 12 years of age. These effects do not vary with differences in sex or sibling interaction/rater contrast effects. Our data reveal higher genetic influences for obsessive-compulsive behavior and do not demonstrate genetic differences across sex.

Background: The goal of this study is to gauge the consistency of Attention Deficit/Hyperactivity Disorder (ADHD) latent class models that are generated by different informants such as adolescents and parents. The consistency of adolescent-derived latent classes from two different samples was assessed and these results were then compared to the class structure generated by parent-report ADHD information., Methods: Self-reported DSM-IV Criterion A ADHD symptoms of 497 adolescent males from a population-based twin study in the state of Missouri (USA) were subjected to principal components and latent class analysis, and findings were compared to previous results obtained from identical analyses using an adolescent sample from Porto Alegre, Brazil (N = 483)., Results: The bi-dimensional structure of self-reported ADHD symptoms was similar for both male adolescent groups, but explained less than 40% of the symptom variance in either sample. Two factors, one with loadings on inattention symptoms only and the other with loadings on hyperactive-impulsive symptoms only, were identified in the Missouri sample. Specific ADHD latent classes did not replicate well across the Missouri and Brazilian samples, and both groups were characterized by the presence of several combined symptom classes but few inattentive or hyperactive-impulsive classes., Conclusions: While adolescent-report information across two different cultures can at least in part reproduce the two-factor structure of ADHD, results from latent class analysis suggest that adolescent reporting on their own symptoms is markedly different from the type of information parents provide about ADHD symptoms in their offspring. The current findings indicate that if male adolescents endorse any ADHD symptoms there is a tendency for them to report combined type problems.