title: Maternal smoking during pregnancy and ADHD: a comprehensive clinical and neurocognitive characterization.
abstract: BACKGROUND
  Evidence from epidemiological studies has consistently shown an association between maternal smoking during pregnancy (MSDP) and attention-deficit/hyperactivity disorder (ADHD). The objective of this study is to test the hypothesis that children with ADHD exposed to MSDP show a distinctive clinical and neurocognitive profile when compared with unexposed children.
  
  
  METHODS
  Four hundred and thirty-six children diagnosed with ADHD were stratified by exposure to MSDP and compared with regard to severity of illness, comorbidity, IQ, and executive function as assessed by a battery of neuropsychological tests. All comparisons were adjusted for socioeconomic status, ethnicity, mother's age at child's birth, and maternal alcohol consumption during pregnancy.
  
  
  RESULTS
  Exposed children had more severe behavioral problems with greater externalizing symptoms and more conduct and oppositional defiant disorder items, lower verbal IQ, and a sluggish cognitive profile on the Continuous Performance Test (CPT). Linear regression analyses revealed a dose-response relationship between the average number of cigarettes smoked per day during pregnancy and verbal IQ, CPT omission errors T score and several other clinical variables.
  
  
  CONCLUSIONS
  These results suggest that MSDP is associated with a more severe form of ADHD, characterized by more severe clinical manifestations and poorer neuropsychological performance. This phenotypic signature associated with MSDP may help to identify a more homogenous subgroup of children with ADHD.
authors.affiliation: Integrated Program in Neuroscience, McGill University, Montréal, Canada.
authors.forename: Geeta A
authors.initials: GA
authors.lastname: Thakur
authors.forename: Sarojini M
authors.initials: SM
authors.lastname: Sengupta
authors.forename: Natalie
authors.initials: N
authors.lastname: Grizenko
authors.forename: Norbert
authors.initials: N
authors.lastname: Schmitz
authors.forename: Véronique
authors.initials: V
authors.lastname: Pagé
authors.forename: Ridha
authors.initials: R
authors.lastname: Joober
mesh_terms: D000328:Adult; D000428:Alcohol Drinking; D001289:Attention Deficit Disorder with Hyperactivity / Q000453:epidemiology / Q000523:psychology*; D002648:Child; D005260:Female; D006801:Humans; D007361:Intelligence Tests; D016014:Linear Models; D008297:Male; D008423:Maternal Age; D009483:Neuropsychological Tests; D011247:Pregnancy; D011297:Prenatal Exposure Delayed Effects; D012907:Smoking / Q000009:adverse effects*; D012923:Social Class