Association of high reaction time variability with the 7-repeat allele absence appears to be the most consistent result and seems to be specific to ADHD .
Speed of processing , set-shifting and cognitive impulsiveness were less frequently investigated but seem to be altered in the 7-repeat allele carriers .
High reaction time variability seems to be the most replicated cognitive marker associated with the 10-repeat homozygosity .
BACKGROUND We review ed systematic ally the results of genetic studies investigating associations between putative susceptibility genes for attention-deficit hyperactivity disorder ( ADHD ) and neuropsychological traits relevant for this disorder .
Maternal smoking habits and cognitive development of children at age 4 years in a population-based birth cohort.
BACKGROUND Active  maternal smoking  during pregnancy has been associated with a higher risk of  behavioural disorders in children , but a few cohort studies measuring smoking data prospect ively have studied its specific effects on the cognitive abilities of pre-schoolers . METHOD A birth cohort was set up in Menorca Isl and in 1997 within the Asthma Multicenter Infants Cohort Study . A total of 420 ( 87 % of those eligible ) children had complete data for final analyses at age 4 years .  Interviewer-administered question naires were completed by mothers during the third trimester of pregnancy and then every year up to age 4 years of their child . A st and ardized version of the McCarthy Scales of Children 's Abilities ( MCSA ) was used to evaluate the child 's motor and cognitive capabilities . Multivariable regressions were used with MCSA 's assessed outcomes adjusting for : home location , maternal alcohol consumption , mother 's social class and level of education during pregnancy , parity , marital status , father 's education level , child 's gender , birth weight and height , breastfeeding duration , passive smoking , school season , age during test administration and evaluator ( psychologist ) . RESULTS A high global consistency in maternal smoking habits was found ( total agreement = 88.7 % ) . Maternal social class and education level were inversely associated with maternal smoking behaviour . Maternal smoking during pregnancy ( in cig./day ) was associated with a decrease ( in points ) of children 's global cognitive score [ beta = -0.60 , ( 95 % CI : -1.10 ; -0.09 ) ] ; as well as global cognitive sub- areas like verbal score [ beta = -0.59 , ( 95 % CI : -1.11 ; -0.07 ) ] ; quantitative score [ beta = -0.57 , ( 95 % CI : -1.08 ; -0.06 ) ] ; executive function score [ beta = -0.71 , ( 95 % CI : -1.23 ; -0.20 ) ] ; and working memory score [ beta = -0.46 , ( 95 % CI : -0.92 ; -0.01 ) ] . CONCLUSION Our findings suggest an association with maternal smoking during pregnancy and lowered cognitive development in children at age 4 years
Association of high reaction time variability with the 7-repeat allele absence appears to be the most consistent result and seems to be specific to ADHD .
Speed of processing , set-shifting and cognitive impulsiveness were less frequently investigated but seem to be altered in the 7-repeat allele carriers .
High reaction time variability seems to be the most replicated cognitive marker associated with the 10-repeat homozygosity .
BACKGROUND We review ed systematic ally the results of genetic studies investigating associations between putative susceptibility genes for attention-deficit hyperactivity disorder ( ADHD ) and neuropsychological traits relevant for this disorder .