BACKGROUND: Attention deficit hyperactivity disorder (ADHD) frequently persists into adulthood. Family and twin studies delineate a disorder with strong genetic influences among children and adolescents based on parent- and teacher-reported data but little is known about the genetic and environmental contribution to DSM-IV ADHD symptoms in adulthood. We therefore aimed to investigate the impact of genetic and environmental influences on the inattentive and hyperactive-impulsive symptoms of ADHD in adults. METHOD: Twin methods were applied to self-reported assessments of ADHD symptoms from a large population-based Swedish twin study that included data from 15 198 Swedish male and female twins aged 20 to 46 years. RESULTS: The broad heritability [i.e., A + D, where A is an additive genetic factor and D (dominance) a non-additive genetic factor] was 37% (A = 11%, D = 26%) for inattention and 38% (A = 18%, D = 20%) for hyperactivity-impulsivity. The results also indicate that 52% of the phenotypic correlation between inattention and hyperactivity-impulsivity (r = 0.43) was explained by genetic influences whereas the remaining part of the covariance was explained by non-shared environmental influences. These results were replicated across age strata. CONCLUSIONS: Our findings of moderate broad heritability estimates are consistent with previous literature on self-rated ADHD symptoms in older children, adolescents and adults and retrospective reports of self-rated childhood ADHD by adults but differ from studies of younger children with informant ratings. Future research needs to clarify whether our data indicate a true decrease in the heritability of ADHD in adults compared to children, or whether this relates to the use of self-ratings in contrast to informant data.
BACKGROUND:Attention deficit hyperactivity disorder (ADHD) frequently persists into adulthood. Family and twin studies delineate a disorder with strong genetic influences among children and adolescents based on parent- and teacher-reported data but little is known about the genetic and environmental contribution to DSM-IV ADHD symptoms in adulthood. We therefore aimed to investigate the impact of genetic and environmental influences on the inattentive and hyperactive-impulsive symptoms of ADHD in adults. METHOD: Twin methods were applied to self-reported assessments of ADHD symptoms from a large population-based Swedish twin study that included data from 15 198 Swedish male and female twins aged 20 to 46 years. RESULTS: The broad heritability [i.e., A + D, where A is an additive genetic factor and D (dominance) a non-additive genetic factor] was 37% (A = 11%, D = 26%) for inattention and 38% (A = 18%, D = 20%) for hyperactivity-impulsivity. The results also indicate that 52% of the phenotypic correlation between inattention and hyperactivity-impulsivity (r = 0.43) was explained by genetic influences whereas the remaining part of the covariance was explained by non-shared environmental influences. These results were replicated across age strata. CONCLUSIONS: Our findings of moderate broad heritability estimates are consistent with previous literature on self-rated ADHD symptoms in older children, adolescents and adults and retrospective reports of self-rated childhood ADHD by adults but differ from studies of younger children with informant ratings. Future research needs to clarify whether our data indicate a true decrease in the heritability of ADHD in adults compared to children, or whether this relates to the use of self-ratings in contrast to informant data.
Authors: A Merwood; C U Greven; T S Price; F Rijsdijk; J Kuntsi; G McLoughlin; H Larsson; P J Asherson Journal: Psychol Med Date: 2013-01-09 Impact factor: 7.723
Authors: C P King; L Militello; A Hart; C L St Pierre; E Leung; C L Versaggi; N Roberson; J Catlin; A A Palmer; J B Richards; P J Meyer Journal: Genes Brain Behav Date: 2017-05-02 Impact factor: 3.449
Authors: Veera M Rajagopal; Jinjie Duan; Laura Vilar-Ribó; Jakob Grove; Tetyana Zayats; J Antoni Ramos-Quiroga; F Kyle Satterstrom; María Soler Artigas; Jonas Bybjerg-Grauholm; Marie Bækvad-Hansen; Thomas D Als; Anders Rosengren; Mark J Daly; Benjamin M Neale; Merete Nordentoft; Thomas Werge; Ole Mors; David M Hougaard; Preben B Mortensen; Marta Ribasés; Anders D Børglum; Ditte Demontis Journal: Nat Genet Date: 2022-08-04 Impact factor: 41.307
Authors: Lucy Riglin; Stephan Collishaw; Ajay K Thapar; Søren Dalsgaard; Kate Langley; George Davey Smith; Evie Stergiakouli; Barbara Maughan; Michael C O'Donovan; Anita Thapar Journal: JAMA Psychiatry Date: 2016-12-01 Impact factor: 21.596