Autism Spectrum Disorders and Other Mental Health Problems: Exploring Etiological Overlaps and Phenotypic Causal Associations

TY - JOUR

T1 - Autism Spectrum Disorders and Other Mental Health Problems

T2 - Exploring Etiological Overlaps and Phenotypic Causal Associations

AU - Tick, Beata

AU - Colvert, Emma

AU - McEwen, Fiona

AU - Stewart, Catherine

AU - Woodhouse, Emma

AU - Gillan, Nicola

AU - Hallett, Victoria

AU - Lietz, Stephanie

AU - Garnett, Tracy

AU - Simonoff, Emily

AU - Ronald, Angelica

AU - Bolton, Patrick

AU - Happé, Francesca

AU - Rijsdijk, Frühling

N1 - Copyright © 2016 American Academy of Child and Adolescent Psychiatry. Published by Elsevier Inc. All rights reserved.

PY - 2016/2

Y1 - 2016/2

N2 - ObjectiveRecent studies have highlighted the impact of coexisting mental health problems in autism spectrum disorders (ASD). No twin studies to date have reported on individuals meeting diagnostic criteria of ASD. This twin study reports on the etiological overlap between the diagnosis of ASD and emotional symptoms, hyperactivity, and conduct problems measured with the Strengths and Difficulties Questionnaire.MethodGenetic and environmental influences on the covariance between ASD and coexisting problems were estimated, in line with the correlated risks model prediction. Phenotypic causality models were also fitted to explore alternative explanations of comorbidity: namely, that coexisting problems are the result of or result in ASD symptoms; that they increase recognition of ASD; or that they arise due to an over-observation bias/confusion when differentiating between phenotypes.ResultsMore than 50% of twins with broad spectrum/ASD met the borderline/abnormal levels cut-off criteria for emotional symptoms or hyperactivity, and approximately 25% met these criteria for the 3 reported problems. In comparison, between 13% and 16% of unaffected twins scored above the cut-offs. The phenotypic correlation between ASD and emotional symptoms was explained entirely by genetic influences and accompanied by a moderate genetic correlation (0.42). The opposite was true for the overlap with conduct problems, as nonshared-environmental factors had the strongest impact. For hyperactivity, the best-fitting model suggested a unidirectional phenotypic influence of hyperactivity on ASD.ConclusionOur findings suggest a possible effect of hyperactivity on identification of ASD. The lack of genetic influences on conduct problems–ASD overlap further supports the genetic independence of these 2 phenotypes. Finally, the co-occurrence of emotional symptoms in ASD, compared to other co-occurring problems, is completely explained by common genetic effects.

AB - ObjectiveRecent studies have highlighted the impact of coexisting mental health problems in autism spectrum disorders (ASD). No twin studies to date have reported on individuals meeting diagnostic criteria of ASD. This twin study reports on the etiological overlap between the diagnosis of ASD and emotional symptoms, hyperactivity, and conduct problems measured with the Strengths and Difficulties Questionnaire.MethodGenetic and environmental influences on the covariance between ASD and coexisting problems were estimated, in line with the correlated risks model prediction. Phenotypic causality models were also fitted to explore alternative explanations of comorbidity: namely, that coexisting problems are the result of or result in ASD symptoms; that they increase recognition of ASD; or that they arise due to an over-observation bias/confusion when differentiating between phenotypes.ResultsMore than 50% of twins with broad spectrum/ASD met the borderline/abnormal levels cut-off criteria for emotional symptoms or hyperactivity, and approximately 25% met these criteria for the 3 reported problems. In comparison, between 13% and 16% of unaffected twins scored above the cut-offs. The phenotypic correlation between ASD and emotional symptoms was explained entirely by genetic influences and accompanied by a moderate genetic correlation (0.42). The opposite was true for the overlap with conduct problems, as nonshared-environmental factors had the strongest impact. For hyperactivity, the best-fitting model suggested a unidirectional phenotypic influence of hyperactivity on ASD.ConclusionOur findings suggest a possible effect of hyperactivity on identification of ASD. The lack of genetic influences on conduct problems–ASD overlap further supports the genetic independence of these 2 phenotypes. Finally, the co-occurrence of emotional symptoms in ASD, compared to other co-occurring problems, is completely explained by common genetic effects.

U2 - 10.1016/j.jaac.2015.11.013

DO - 10.1016/j.jaac.2015.11.013

M3 - Article

C2 - 26802777

SN - 0890-8567

VL - 55

SP - 106-113.e4

JO - Journal of the American Academy of Child and Adolescent Psychiatry

JF - Journal of the American Academy of Child and Adolescent Psychiatry

IS - 2

ER -