ABSTRACT
OBJECTIVE: To determine the 5-year prospective stability of population-based and DSM-IV subtypes of attention-deficit/hyperactivity disorder (ADHD) as well as to explore predictors of stability. METHOD: A total of 708 twins ages 7 to 19 years who were identified from birth records of the state of Missouri and had participated in a study of ADHD were reassessed 5 years later in a blinded fashion. Stabilities of DSM-IV and population-based ADHD subtypes were compared using percentage of agreement with significance tested by the kappa statistic. Predictors of stability of subtype diagnosis were determined using multivariate logistic regression. RESULTS: In general, 5-year ADHD subtype stability was poor to modest and ranged from 11.1% to 24.0% for DSM-IV for subtypes and from 14.3% to 35.3% for clinically significant population-derived subtypes. There were no predictors of diagnostic stability that applied across subtypes. There were subtype-specific predictors including a diagnosis of oppositional defiant disorder for DSM-IV primarily inattentive ADHD; lower verbal IQ for DSM-IV combined type ADHD; and younger age, oppositional defiant disorder, and medication use for population-defined severe combined ADHD. CONCLUSIONS: Population-defined ADHD subtype criteria demonstrated modestly improved diagnostic stability over 5 years compared to DSM-IV subtypes. Few correlates or predictors of stability were identified.
Subject(s)
Attention Deficit Disorder with Hyperactivity/diagnosis , Diseases in Twins/diagnosis , Adolescent , Adult , Attention Deficit Disorder with Hyperactivity/classification , Attention Deficit Disorder with Hyperactivity/genetics , Attention Deficit Disorder with Hyperactivity/psychology , Attention Deficit and Disruptive Behavior Disorders/classification , Attention Deficit and Disruptive Behavior Disorders/diagnosis , Attention Deficit and Disruptive Behavior Disorders/genetics , Attention Deficit and Disruptive Behavior Disorders/psychology , Child , Comorbidity , Diagnostic and Statistical Manual of Mental Disorders , Diseases in Twins/classification , Diseases in Twins/genetics , Diseases in Twins/psychology , Female , Genetic Predisposition to Disease/genetics , Humans , Male , Phenotype , Prognosis , Prospective StudiesABSTRACT
BACKGROUND: To test whether the retrospective reporting of the age of onset impairment criterion for attention deficit/hyperactivity disorder (ADHD) required in the Diagnostic and Statistical Manual of Mental Disorders - IV (DSM-IV) complicates identification of new and known child and adolescent cases later in life. METHODS: A birth-records-based cohort of twins assessed at ages 7 to 19 years were blindly reassessed five years later using the MAGIC interview. Study outcome measures were differences in reported ages of onset for attention deficit/hyperactivity disorder (ADHD), oppositional defiant disorder (ODD), conduct disorder (CD) and major depressive disorder (MDD). RESULTS: For all age groups and respondents (parent on youth or youth self-report), later ages of ADHD onset were reported five years later. The same phenomenon was also present for the other diagnostic groups. Of the initial ADHD individuals who continued to meet all other ADHD criteria at follow-up, 46% failed the age of onset criterion five years later. When ignoring the age of onset criterion, late onsets of ages 7-16 years accounted for about 10% of all ADHD. CONCLUSIONS: Use of the DSM-IV age of onset criterion for attention deficit/hyperactivity disorder in the assessment of adolescents and young adults results in under-identification of affected individuals. Consideration should be given to revising the current nomenclatures to reflect the reality of retrospective reporting errors in age of onset as well as the presence of late onset cases.
Subject(s)
Attention Deficit Disorder with Hyperactivity/diagnosis , Attention Deficit Disorder with Hyperactivity/epidemiology , Attention Deficit and Disruptive Behavior Disorders/diagnosis , Attention Deficit and Disruptive Behavior Disorders/epidemiology , Diagnostic and Statistical Manual of Mental Disorders , Adolescent , Adult , Age of Onset , Child , Female , Humans , Interview, Psychological , Male , Psychiatric Status Rating Scales , Young AdultABSTRACT
BACKGROUND: In utero exposure to smoking and alcohol are common risk factors that have been associated with attention-deficit/hyperactivity disorder (ADHD) in human beings and animal models. Furthermore, molecular studies have focused on the association between ADHD and DNA polymorphisms in dopamine pathway-related genes. We examined the joint effects of genetic and prenatal substance exposures on DSM-IV and population-defined subtypes of ADHD. METHODS: Logistic regression was used to assess the relationship between ADHD subtypes, DAT1 and DRD4 polymorphisms, and prenatal substance exposures in a birth-record sample of male and female twin pairs, aged 7-19 years. RESULTS: Interactions between prenatal exposure to smoking and variations in the DAT1 and DRD4 loci were observed in children with either the DSM-IV or population-defined ADHD combined subtypes. The odds of a diagnosis of DSM-IV combined subtype was 2.9 times greater in twins who had inherited the DAT1 440 allele and who were exposed, than in unexposed twins without the risk allele. The OR was 2.6 in the population-defined subtype. Odds ratios for the DRD4 seven-repeat allele were 3.0 (2.8) in the population-defined (DSM-IV) combined ADHD subtypes. The OR for exposed children with both alleles was 9.0 (95% confidence interval=2.0-41.5) for the population-defined combined subtypes. CONCLUSIONS: Results indicate that smoking during pregnancy is associated with specific subtypes of ADHD in genetically susceptible children.