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- Quinn, Patrick D., et al.
(författare)
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Childhood attention-deficit/hyperactivity disorder symptoms and the development of adolescent alcohol problems : A prospective, population-based study of Swedish twins
- 2016
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Ingår i: American Journal of Medical Genetics Part B. - Hoboken, USA : John Wiley & Sons. - 1552-4841 .- 1552-485X. ; 171:7, s. 958-970
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Tidskriftsartikel (refereegranskat)abstract
- Children with attention-deficit/hyperactivity disorder (ADHD) are at increased risk of problematic alcohol and other substance use in adolescence. This study used data from an ongoing, prospective, population-based twin study of Swedish children and adolescents to evaluate the extent to which the association between ADHD symptoms and alcohol problems reflects a unique source of genetic or environmental risk related to ADHD versus a broader predisposition to youth externalizing behavior. We used all available data from same-sex monozygotic (MZ) and dizygotic (DZ) twins on ADHD symptoms in childhood (age 9/12; N = 15,549) and alcohol problems in late adolescence (age 18; N = 2,564). Consistent with prior longitudinal studies, the phenotypic association between hyperactive/impulsive ADHD symptoms and alcohol problems was small in magnitude, whereas the association for inattentive symptoms was even weaker. Additive genetic influences explained 99.8% of the association between hyperactive/impulsive symptoms and alcohol problems. Furthermore, we found that the genetic risk specifically associated with hyperactive/impulsive symptoms was attenuated when estimated in the context of externalizing behavior liability during childhood, of which ADHD symptoms were specific expressions. In sensitivity analyses exploring hyperactivity in mid-adolescence, we found a similar pattern of genetic associations. These results are consistent with previous findings of genetically driven overlap in the etiology of ADHD and problematic alcohol use. At least some of this co-occurrence may result from a general predisposition to externalizing behaviors in youth. © 2015 Wiley Periodicals, Inc.
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| 2. |
- Rydell, Mina, et al.
(författare)
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Genetic and environmental contributions to the association between ADHD and affective problems in early childhood : A Swedish population-based twin study
- 2017
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Ingår i: American Journal of Medical Genetics Part B. - Stockholm : John Wiley & Sons. - 1552-4841 .- 1552-485X. ; 174:5, s. 538-546
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Tidskriftsartikel (refereegranskat)abstract
- Few twin studies have explored the relative contribution of genetic and environmental factors to the association between attention deficit hyperactivity disorder (ADHD) and affective problems, and no study has focused on preschool children. We used the classical twin design to explore the genetic and environmental overlap between ADHD symptoms and affective problems in preschool children, based on 879 five-year-old twin pairs born in Sweden 2004-2005. Questionnaire-based parent-ratings were used to measure ADHD symptoms and affective problems. A bivariate twin design was used to decompose variance in ADHD and affective problems into genetic and environmental components, and to test the degree to which these components overlapped across the two traits. Our results showed that there was a significant correlation of 0.34 (95% Confidence Interval [CI] 0.29-0.38) between ADHD and affective problems. This correlation was mostly explained by additive genetic factors (64%, 95%CI 37-93%), and to a lesser extent by shared environmental factors (35%, 95%CI 10-59%). Nonshared environmental factors did not contribute to the correlation between ADHD and affective problems (0%, 95%CI -9 to 10%). These findings show that there is a significant association between ADHD and affective problems in preschool children that is mostly explained by genetic influences. This adds important knowledge about the etiology of both ADHD and affective problems by indicating that these phenotypes are linked from as early as preschool years. This also needs to be taken into consideration when diagnosing young children and clinicians should consider assessing both affective problems and ADHD if one is present.
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| 3. |
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| 4. |
- Bergen, SE, et al.
(författare)
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National-scale precision medicine for psychiatric disorders in Sweden
- 2018
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Ingår i: American journal of medical genetics. Part B, Neuropsychiatric genetics : the official publication of the International Society of Psychiatric Genetics. - : Wiley. - 1552-485X. ; 177:7, s. 630-634
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Tidskriftsartikel (refereegranskat)
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| 7. |
- Brikell, Isabell, et al.
(författare)
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Heritability of attention-deficit hyperactivity disorder in adults
- 2015
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Ingår i: American Journal of Medical Genetics Part B. - Hoboken, USA : Wiley-Blackwell. - 1552-4841 .- 1552-485X. ; 168:6, s. 406-413
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Forskningsöversikt (refereegranskat)abstract
- Attention-deficit/hyperactivity disorder (ADHD) is a common neurodevelopmental disorder. Symptoms often persist into adulthood, with a prevalence of 2.5-5% in adult populations. Twin studies in childhood consistently report high heritabilities of 70-80%, while studies in adult samples show only moderate heritability of 30-40% when estimated from self-ratings. This review summarizes the available research on the heritability of ADHD in adults. Three key findings are outlined: (i) self-ratings lead to relatively low heritability estimates of ADHD, independent of age and whether ratings refer to current or retrospective symptoms; (ii) studies relying on different informants to rate each twin within a pair (i.e., self-ratings and different parents/teachers rating each twin in a pair) consistently yield lower heritability estimates than studies relying on ratings from a single informant; (iii) studies using cross-informant data via either combined parent and self-ratings or clinical diagnoses information suggest that the heritability of ADHD in adults could be as high as 70-80%. Together, the reviewed studies suggest that the previously reported low heritability of ADHD in adults is unlikely to reflect a true developmental change. Instead, the drop in heritability is better explained by rater effects related to a switch from using one rater for both twins in a pair (parent/teacher) in childhood, to relying on self-ratings (where each twin rates themselves) of ADHD symptoms in adulthood. When rater effects are addressed using cross-informant approaches, the heritability of ADHD in adults appears to be comparable to the heritability of ADHD in childhood.
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| 8. |
- Chen, Tian-Jiao, et al.
(författare)
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Genetic and environmental influences on the relationship between ADHD symptoms and internalizing problems : A Chinese twin study
- 2016
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Ingår i: American Journal of Medical Genetics Part B. - Hoboken, USA : John Wiley & Sons. - 1552-4841 .- 1552-485X. ; 171:7, s. 931-937
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Tidskriftsartikel (refereegranskat)abstract
- Several twin studies have investigated the overlap between attention deficit hyperactivity disorder (ADHD) and externalizing problems; however, limited information is known regarding the genetic and environmental contribution to the overlap between ADHD and internalizing problems. This study examined the genetic and environmental influences on the variation in and covariation between ADHD symptoms and internalizing problems by using the Child Behavior Checklist (CBCL). We investigated 1,316 child and adolescent twins, including 780 monozygotic twins and 536 dizygotic twins, aged 6 years to 18 years from the Chinese Child and Adolescent Twin Registry. ADHD symptoms and internalizing problems were quantified through parent rating by using the Attention Problems Scale and other three scales, which include Anxious/Depressed, Withdrawn, and Somatic Complaints of CBCL. Genetic and environmental susceptibilities common to ADHD symptoms and internalizing problems were examined through bivariate twin modeling. Results showed that genetic factors substantially influenced the ADHD symptoms with a heritability of 72%. Modest genetic influences and substantial shared environmental influences (20-77%) were observed in the three internalizing problem scales. Common genetic and shared environmental influences were essential for the overlap between ADHD and the three internalizing problems respectively. Approximately one-fifth of the genetic variance of ADHD symptoms was shared with anxiety/depression. In conclusion, substantial genetic and shared environmental influences on ADHD symptoms and internalizing problems were observed in Chinese children and adolescents. Our finding supports a common etiology between ADHD and internalizing problems. This finding can also help explain the co-existence of these behavior problems. © 2015 Wiley Periodicals, Inc.
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