Assessing aetiological overlap between child and adult attention-deficit hyperactivity disorder symptoms in an extended family design

Daniel L Wechsler; Fruhling V Rijsdijk; Nicoletta Adamo; Espen M Eilertsen; Yasmin I Ahmadzadeh; Isabella Badini; Laurie J Hannigan; Eivind Ystrom; Tom A McAdams

doi:10.1192/bjo.2023.554

Assessing aetiological overlap between child and adult attention-deficit hyperactivity disorder symptoms in an extended family design

BJPsych Open. 2023 Sep 6;9(5):e169. doi: 10.1192/bjo.2023.554.

Authors

Daniel L Wechsler¹, Fruhling V Rijsdijk², Nicoletta Adamo³, Espen M Eilertsen⁴, Yasmin I Ahmadzadeh⁵, Isabella Badini⁵, Laurie J Hannigan⁶, Eivind Ystrom⁷, Tom A McAdams⁸

Affiliations

¹ Department of Psychology, Institute of Psychiatry, Psychology and Neuroscience, King's College London, UK.
² Social, Genetic and Developmental Psychiatry Centre, Institute of Psychiatry, Psychology and Neuroscience, King's College London, UK; and Department of Psychology, Faculty of Social Sciences, Anton de Kom University, Suriname.
³ Social, Genetic and Developmental Psychiatry Centre, Institute of Psychiatry, Psychology and Neuroscience, King's College London, UK; and South London and Maudsley NHS Foundation Trust, London, UK.
⁴ PROMENTA Research Centre, University of Oslo, Norway; and Centre for Fertility and Health, Norwegian Institute of Public Health, Oslo, Norway.
⁵ Social, Genetic and Developmental Psychiatry Centre, Institute of Psychiatry, Psychology and Neuroscience, King's College London, UK.
⁶ Department of Mental Disorders, Norwegian Institute of Public Health, Oslo, Norway; Nic Waals Institute, Lovisenberg Diaconal Hospital, Oslo, Norway; and Medical Research Council Integrative Epidemiology Unit, University of Bristol, UK.
⁷ PROMENTA Research Centre, University of Oslo, Norway; Department of Mental Disorders, Norwegian Institute of Public Health, Oslo, Norway; and School of Pharmacy, University of Oslo, Norway.
⁸ Social, Genetic and Developmental Psychiatry Centre, Institute of Psychiatry, Psychology and Neuroscience, King's College London, UK; and PROMENTA Research Centre, University of Oslo, Norway.

Abstract

Background: Several longitudinal studies have cast doubt on the aetiological overlap between child and adult attention-deficit hyperactivity disorder (ADHD). However, a lack of genetically sensitive data following children across adulthood precludes direct evaluation of aetiological overlap between child and adult ADHD.

Aims: We circumvent the existing gap in longitudinal data by exploring genetic overlap between maternal (adult) and offspring (child) ADHD and comorbid symptoms in an extended family cohort.

Method: Data were drawn from the Norwegian Mother, Father and Child Cohort Study, a Norwegian birth registry cohort of 114 500 children and their parents. Medical Birth Registry of Norway data were used to link extended families. Mothers self-reported their own ADHD symptoms when children were aged 3 years; reported children's ADHD symptoms at age 5 years; and children's ADHD, oppositional defiant disorder (ODD), conduct disorder, anxiety and depression symptoms at age 8 years. Genetic correlations were derived from Multiple-Children-of-Twins-and-Siblings and extended bivariate twin models.

Results: Phenotypic correlations between adult ADHD symptoms and child ADHD, ODD, conduct disorder, anxiety and depression symptoms at age 8 years were underpinned by medium-to-large genetic correlations (child ADHD: r_G = 0.55, 95% CI 0.43-0.93; ODD: r_G = 0.80, 95% CI 0.46-1; conduct disorder: r_G = 0.44, 95% CI 0.28-1; anxiety: r_G = 0.72, 95% CI 0.48-1; depression: r_G = 1, 95% CI 0.66-1). These cross-generational adult-child genetic correlations were of a comparable magnitude to equivalent child-child genetic correlations with ADHD symptoms at age 5 years.

Conclusions: Our findings provide genetically sensitive evidence that ADHD symptoms in adulthood share a common genetic architecture with symptoms of ADHD and four comorbid disorders at age 8 years. These findings suggest that in the majority of cases, ADHD symptoms in adulthood are not aetiologically distinct from in childhood.

Keywords: Comorbidity; Medical Birth Registry of Norway; aetiology; attention-deficit hyperactivity disorders; genetics.

Abstract

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