title: Variation in Latent Classes of Adult Attention-Deficit Hyperactivity Disorder by Sex and Environmental Adversity.
abstract: The findings of genetic, imaging and neuropsychological studies of attention-deficit hyperactivity disorder (ADHD) are mixed. To understand why this might be the case we use both dimensional and categorical symptom measurement to provide alternate and detailed perspectives of symptom expression.
  
  
  
  Interviewers collected ADHD, conduct problems (CP) and sociodemographic data from 3793 twins and their siblings aged 22 to 49 (M = 32.6). We estimate linear weighting of symptoms across ADHD and CP items. Latent class analyses and regression describe associations between measured variables, environmental risk factors and subsequent disadvantage. Additionally, the clinical relevance of each class was estimated.
  
  
  
  Five classes were found for women and men; few symptoms, hyperactive-impulsive, CP, inattentive, combined symptoms with CP. Women within the inattentive class reported more symptoms and reduced emotional health when compared to men and to women within other latent classes. Women and men with combined ADHD symptoms reported comorbid conduct problems but those with either inattention or hyperactivity-impulsivity only did not.
  
  
  
  The dual perspective of dimensional and categorical measurement of ADHD provides important detail about symptom variation across sex and with environmental covariates.
authors.affiliation: University of New England, Australia Queensland Institute of Medical Research, Australia Jane.Ebejer@qimr.edu.au.
authors.forename: Jane L
authors.initials: JL
authors.lastname: Ebejer
authors.affiliation: Queensland Institute of Medical Research, Australia.
authors.forename: Sarah E
authors.initials: SE
authors.lastname: Medland
authors.affiliation: University of New England, Australia.
authors.forename: Julius
authors.initials: J
authors.lastname: van der Werf
authors.affiliation: Queensland Institute of Medical Research, Australia King's College London, UK.
authors.forename: Michael
authors.initials: M
authors.lastname: Lynskey
authors.affiliation: Queensland Institute of Medical Research, Australia.
authors.forename: Nicholas G
authors.initials: NG
authors.lastname: Martin
authors.affiliation: Queensland Institute of Medical Research, Australia.
authors.forename: David L
authors.initials: DL
authors.lastname: Duffy
mesh_terms: D000293:Adolescent; D000328:Adult; D001289:Attention Deficit Disorder with Hyperactivity / Q000145:classification / Q000175:diagnosis* / Q000453:epidemiology / Q000523:psychology; D001315:Australia / Q000453:epidemiology; D015897:Comorbidity; D019955:Conduct Disorder / Q000175:diagnosis* / Q000453:epidemiology; D005260:Female; D006801:Humans; D006948:Hyperkinesis / Q000000981:diagnostic imaging*; D007175:Impulsive Behavior; D008297:Male; D008603:Mental Health; D008875:Middle Aged; D019964:Mood Disorders / Q000175:diagnosis* / Q000453:epidemiology; D012307:Risk Factors; D035781:Siblings; D014427:Twins; D055815:Young Adult
keywords: adult ADHD; conduct problems; impulsivity; inattention