The Child and Adolescent Twin Study in Sweden (CATSS)

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The aim of this study is to investigate how both genetic and environmental effects influence health and behavior in children and adolescents.

Project description

We initiated the ongoing CATSS study in 2004. In CATSS-9, we conduct a telephone interview with parents of all 1,400 twin pairs born in Sweden annually in connection with their 9th birthdays. By April 2014 we have performed 13,500 interviews with a high response rate (≈80%), and we have collected DNA from the twins (current N≈14,000 individuals). We follow these families with questionnaires to parents and twins at age 15 (CATSS-15; current N=5,553) and 18 (CATSS-18; current N=2,663 twins) (1).

CATSS is very large and thus has power to study rare conditions and identify subgroups of twins for follow up studies. Since we have information from 10 age cohorts assessed with the same measure we can here investigate how mental health problems among children have changed over time. There is one completed high-risk clinical study (at age 15; CATSS-DOGSS: N=227 twin pairs), four ongoing (CATSS-9-clinic; CATSS-RATSS [ASD]; CATSS-asthma; CATSS-OCD [obsessive compulsive disorder/hoarding). In CATSS-9-clinic we do clinical examinations on twins who screen positive for a neurodevelopmental disorder in the CATSS-9 screening. The main aim is to understand health service inequalities, and to identify factors that predict contact with child and adolescent psychiatry services.

Using the CATSS data we have shown that the heritability for ASD was around 80% and that ASD had a common genetic etiology with other neuropsychiatric disorders (2), that extreme values of ASD (3) and ADHD (4) have the same genetic etiology as normal variation in the underlying traits, and an association between fetal growth on ASD suggesting that fetal growth is in the causal pathway (5). At least 11 theses and 30 papers have up to now been published from the CATSS-study.

Project leader


Paul Lichtenstein

Phone: 08-524 874 24
Organizational unit: Department of Medical Epidemiology and Biostatistics (MEB), C8


We are happy to answer your questions and can be reached by e-mail to

Project period: 2004-ongoing

Present status

The response frequency of the telephone interview is 80%. By November 2008, 7408 interviews had taken place.


Project staff

System developer

Camilla Palm

Phone: 08-524 844 49

System developer

Isabelle Kizling

Phone: 08-524 823 07
Organizational unit: Department of Medical Epidemiology and Biostatistics (MEB), C8


Yi Lu

Phone: 08-524 877 72


Mark Taylor

Phone: 08-524 822 67
Organizational unit: Department of Medical Epidemiology and Biostatistics (MEB), C8

PhD student

Agnes Ohlsson Gotby

Organizational unit: Department of Medical Epidemiology and Biostatistics (MEB), C8

PhD student

Martin Cederlöf

Phone: 08-524 822 06
Organizational unit: Department of Medical Epidemiology and Biostatistics (MEB), C8

Assistant professor

Erik Pettersson


Published theses

Ongoing thesis work


  1. Taylor M, Lichtenstein P, Larsson H, Anckarsäter H, Greven CU, Ronald A. Is there a female protective effect against ADHD? Evidence from two representative twin samples. . J Am Acad Child Adolescent Psych In press.   
  2. Quinn PD, Pettersson E, Lundström S, Anckarsäter H, Långström N, Gumpert CH, Larsson H, Lichtenstein P, D’Onofrio BM. Childhood attention-deficit/hyperactivity disorder symptoms and the development of adolescent alcohol problems: A prospective, population-based study of Swedish twins. . Am J Med Genet Part B: Neuropsych Genet In press.   
  3. Lester N, Garcia D, Lundström S, Brändström S, Råstam M, Nilsson T, Cloninger R, Anckarsäter H. The Genetic and Environmental Structure of the Character Sub-Scales of the Temperament and Character Inventory in Adolescence. . Annals of General Psychiatry In press.   
  4. Antisocial behavior and polymorphisms in the oxytocin receptor gene: findings in two independent samples.
    Hovey D, Lindstedt M, Zettergren A, Jonsson L, Johansson A, Melke J, et al
    Mol. Psychiatry 2016 Jul;21(7):983-8
  5. Further investigations of the relation between polymorphisms in sex steroid related genes and autistic-like traits.
    Zettergren A, Karlsson S, Hovey D, Jonsson L, Melke J, Anckarsäter H, et al
    Psychoneuroendocrinology 2016 Jun;68():1-5
  6. Heritability and confirmation of genetic association studies for childhood asthma in twins.
    Ullemar V, Magnusson P, Lundholm C, Zettergren A, Melén E, Lichtenstein P, et al
    Allergy 2016 Feb;71(2):230-8
  7. Effect of co-twin gender on neurodevelopmental symptoms: a twin register study.
    Eriksson J, Lundström S, Lichtenstein P, Bejerot S, Eriksson E
    Mol Autism 2016 ;7():8
  8. The association between childhood autistic traits and adolescent psychotic experiences is explained by general neuropsychiatric problems.
    Cederlöf M, Pettersson E, Sariaslan A, Larsson H, Östberg P, Kelleher I, et al
    Am. J. Med. Genet. B Neuropsychiatr. Genet. 2016 Mar;171B(2):153-9
  9. Predictors of adolescents' consent to use health records for research and results from data collection in a Swedish twin cohort.
    Ullemar V, Lundholm C, Örtqvist A, Gumpert C, Anckarsäter H, Lundström S, et al
    Twin Res Hum Genet 2015 Jun;18(3):256-65
  10. Childhood neurodevelopmental problems and adolescent bully victimization: population-based, prospective twin study in Sweden.
    Törn P, Pettersson E, Lichtenstein P, Anckarsäter H, Lundström S, Hellner Gumpert C, et al
    Eur Child Adolesc Psychiatry 2015 Sep;24(9):1049-59
  11. Birth weight as an independent predictor of ADHD symptoms: a within-twin pair analysis.
    Pettersson E, Sjölander A, Almqvist C, Anckarsäter H, D'Onofrio B, Lichtenstein P, et al
    J Child Psychol Psychiatry 2015 Apr;56(4):453-9
  12. Childhood Symptoms of ADHD Overrule Comorbidity in Relation to Psychosocial Outcome at Age 15: A Longitudinal Study.
    Norén Selinus E, Molero Y, Lichtenstein P, Larson T, Lundström S, Anckarsäter H, et al
    PLoS ONE 2015 ;10(9):e0137475
  13. Personality and intelligence: persistence, not self-directedness, cooperativeness or self-transcendence, is related to twins' cognitive abilities.
    Mousavi F, Rozsa S, Nilsson T, Archer T, Anckarsäter H, Garcia D
    PeerJ 2015 ;3():e1195
  14. Multimodal brain imaging in autism spectrum disorder and the promise of twin research.
    Mevel K, Fransson P, Bölte S
    Autism 2015 Jul;19(5):527-41
  15. Autism spectrum disorders and coexisting disorders in a nationwide Swedish twin study.
    Lundström S, Reichenberg A, Melke J, Råstam M, Kerekes N, Lichtenstein P, et al
    J Child Psychol Psychiatry 2015 Jun;56(6):702-10
  16. Autism phenotype versus registered diagnosis in Swedish children: prevalence trends over 10 years in general population samples.
    Lundström S, Reichenberg A, Anckarsäter H, Lichtenstein P, Gillberg C
    BMJ 2015 Apr;350():h1961
  17. Neurodevelopmental problems and extremes in BMI.
    Kerekes N, Tajnia A, Lichtenstein P, Lundström S, Anckarsäter H, Nilsson T, et al
    PeerJ 2015 ;3():e1024
  18. Impact of asthma medication and familial factors on the association between childhood asthma and attention-deficit/hyperactivity disorder: a combined twin- and register-based study: Epidemiology of Allergic Disease.
    Holmberg K, Lundholm C, Anckarsäter H, Larsson H, Almqvist C
    Clin. Exp. Allergy 2015 May;45(5):964-73
  19. Cohort Profile: Swedish Twin Study on Prediction and Prevention of Asthma (STOPPA).
    Almqvist C, Örtqvist A, Ullemar V, Lundholm C, Lichtenstein P, Magnusson P
    Twin Res Hum Genet 2015 Jun;18(3):273-80
  20. Willfors C, Ronald A, Berggren S, L. P, Lichtenstein P, Anckarsater H, Coco C, Bölte S. On the role of non-shared environment for executive functioning in ADHD: a twin-differences design study Int J Dev Disabilities 2014;60:163-73.   
  21. Symptoms of autism and ADHD: a Swedish twin study examining their overlap.
    Ronald A, Larsson H, Anckarsäter H, Lichtenstein P
    J Abnorm Psychol 2014 May;123(2):440-51
  22. Reliability of Autism-Tics, AD/HD, and other Comorbidities (A-TAC) inventory in a test-retest design.
    Larson T, Kerekes N, Selinus E, Lichtenstein P, Gumpert C, Anckarsäter H, et al
    Psychol Rep 2014 Feb;114(1):93-103
  23. Oppositional defiant- and conduct disorder-like problems: neurodevelopmental predictors and genetic background in boys and girls, in a nationwide twin study.
    Kerekes N, Lundström S, Chang Z, Tajnia A, Jern P, Lichtenstein P, et al
    PeerJ 2014 ;2():e359
  24. Association study between autistic-like traits and polymorphisms in the autism candidate regions RELN, CNTNAP2, SHANK3, and CDH9/10.
    Jonsson L, Zettergren A, Pettersson E, Hovey D, Anckarsäter H, Westberg L, et al
    Mol Autism 2014 ;5(1):55
  25. Association between ASMT and autistic-like traits in children from a Swedish nationwide cohort.
    Jonsson L, Anckarsäter H, Zettergren A, Westberg L, Walum H, Lundström S, et al
    Psychiatr. Genet. 2014 Feb;24(1):21-7
  26. Associations between oxytocin-related genes and autistic-like traits.
    Hovey D, Zettergren A, Jonsson L, Melke J, Anckarsäter H, Lichtenstein P, et al
    Soc Neurosci 2014 ;9(4):378-86
  27. Relative immaturity and ADHD: findings from nationwide registers, parent- and self-reports.
    Halldner L, Tillander A, Lundholm C, Boman M, Långström N, Larsson H, et al
    J Child Psychol Psychiatry 2014 Aug;55(8):897-904
  28. Motor function and perception in children with neuropsychiatric and conduct problems: results from a population based twin study.
    Gustafsson P, Kerekes N, Anckarsäter H, Lichtenstein P, Gillberg C, Råstam M
    J Neurodev Disord 2014 ;6(1):11
  29. Exposure to air pollution from traffic and neurodevelopmental disorders in Swedish twins.
    Gong T, Almqvist C, Bölte S, Lichtenstein P, Anckarsäter H, Lind T, et al
    Twin Res Hum Genet 2014 Dec;17(6):553-62
  30. Responsibility and cooperativeness are constrained, not determined.
    Garcia D, Stråge A, Lundström S, Radovic S, Brändström S, Råstam M, et al
    Front Psychol 2014 ;5():308
  31. Language and mathematical problems as precursors of psychotic-like experiences and juvenile mania symptoms.
    Cederlöf M, Ostberg P, Pettersson E, Anckarsäter H, Gumpert C, Lundström S, et al
    Psychol Med 2014 Apr;44(6):1293-302
  32. The Roots of Autism and ADHD Twin Study in Sweden (RATSS).
    Bölte S, Willfors C, Berggren S, Norberg J, Poltrago L, Mevel K, et al
    Twin Res Hum Genet 2014 Jun;17(3):164-76
  33. Associations between polymorphisms in sex steroid related genes and autistic-like traits.
    Zettergren A, Jonsson L, Johansson D, Melke J, Lundström S, Anckarsäter H, et al
    Psychoneuroendocrinology 2013 Nov;38(11):2575-84
  34. Examining and interpreting the female protective effect against autistic behavior.
    Robinson E, Lichtenstein P, Anckarsäter H, Happé F, Ronald A
    Proc. Natl. Acad. Sci. U.S.A. 2013 Mar;110(13):5258-62
  35. Eating problems and overlap with ADHD and autism spectrum disorders in a nationwide twin study of 9- and 12-year-old children.
    Råstam M, Täljemark J, Tajnia A, Lundström S, Gustafsson P, Lichtenstein P, et al
    ScientificWorldJournal 2013 ;2013():315429
  36. Different neurodevelopmental symptoms have a common genetic etiology.
    Pettersson E, Anckarsäter H, Gillberg C, Lichtenstein P
    J Child Psychol Psychiatry 2013 Dec;54(12):1356-65
  37. A study of the possible association between adenosine A2A receptor gene polymorphisms and attention-deficit hyperactivity disorder traits.
    Molero Y, Gumpert C, Serlachius E, Lichtenstein P, Walum H, Johansson D, et al
    Genes Brain Behav. 2013 Apr;12(3):305-10
  38. The Swedish Twin Registry: establishment of a biobank and other recent developments.
    Magnusson P, Almqvist C, Rahman I, Ganna A, Viktorin A, Walum H, et al
    Twin Res Hum Genet 2013 Feb;16(1):317-29
  39. Predictive properties of the A-TAC inventory when screening for childhood-onset neurodevelopmental problems in a population-based sample.
    Larson T, Lundström S, Nilsson T, Selinus E, Råstam M, Lichtenstein P, et al
    BMC Psychiatry 2013 Sep;13():233
  40. ADHD, autism spectrum disorder, temperament, and character: phenotypical associations and etiology in a Swedish childhood twin study.
    Kerekes N, Brändström S, Lundström S, Råstam M, Nilsson T, Anckarsäter H
    Compr Psychiatry 2013 Nov;54(8):1140-7
  41. Prevalence, comorbidity and heritability of hoarding symptoms in adolescence: a population based twin study in 15-year olds.
    Ivanov V, Mataix-Cols D, Serlachius E, Lichtenstein P, Anckarsäter H, Chang Z, et al
    PLoS ONE 2013 ;8(7):e69140
  42. Temperament and character in the Child and Adolescent Twin Study in Sweden (CATSS): comparison to the general population, and genetic structure analysis.
    Garcia D, Lundström S, Brändström S, Råstam M, Cloninger C, Kerekes N, et al
    PLoS ONE 2013 ;8(8):e70475
  43. Self-directedness and cooperativeness, psychosocial dysfunction and suffering in ESSENCE.
    Garcia D, Anckarsäter H, Lundström S
    ScientificWorldJournal 2013 ;2013():416981
  44. Childhood behavior problems and adolescent sexual risk behavior: familial confounding in the child and adolescent twin study in Sweden (CATSS).
    Donahue K, Lichtenstein P, Lundström S, Anckarsäter H, Gumpert C, Långström N, et al
    J Adolesc Health 2013 May;52(5):606-12
  45. Variation in the oxytocin receptor gene is associated with pair-bonding and social behavior.
    Walum H, Lichtenstein P, Neiderhiser J, Reiss D, Ganiban J, Spotts E, et al
    Biol. Psychiatry 2012 Mar;71(5):419-26
  46. Autism spectrum disorders and autistic like traits: similar etiology in the extreme end and the normal variation.
    Lundström S, Chang Z, Råstam M, Gillberg C, Larsson H, Anckarsäter H, et al
    Arch. Gen. Psychiatry 2012 Jan;69(1):46-52
  47. Lower birth weight indicates higher risk of autistic traits in discordant twin pairs.
    Losh M, Esserman D, Anckarsäter H, Sullivan P, Lichtenstein P
    Psychol Med 2012 May;42(5):1091-102
  48. Childhood attention-deficit hyperactivity disorder as an extreme of a continuous trait: a quantitative genetic study of 8,500 twin pairs.
    Larsson H, Anckarsater H, Råstam M, Chang Z, Lichtenstein P
    J Child Psychol Psychiatry 2012 Jan;53(1):73-80
  49. A twin study of autism symptoms in Sweden.
    Ronald A, Larsson H, Anckarsäter H, Lichtenstein P
    Mol. Psychiatry 2011 Oct;16(10):1039-47
  50. Autistic-like traits and their association with mental health problems in two nationwide twin cohorts of children and adults.
    Lundström S, Chang Z, Kerekes N, Gumpert C, Råstam M, Gillberg C, et al
    Psychol Med 2011 Nov;41(11):2423-33
  51. Heritability of cortisol regulation in children.
    Gustafsson P, Gustafsson P, Anckarsäter H, Lichtenstein P, Ljung T, Nelson N, et al
    Twin Res Hum Genet 2011 Dec;14(6):553-61
  52. The Child and Adolescent Twin Study in Sweden (CATSS).
    Anckarsäter H, Lundström S, Kollberg L, Kerekes N, Palm C, Carlström E, et al
    Twin Res Hum Genet 2011 Dec;14(6):495-508
  53. Trajectories leading to autism spectrum disorders are affected by paternal age: findings from two nationally representative twin studies.
    Lundström S, Haworth C, Carlström E, Gillberg C, Mill J, Råstam M, et al
    J Child Psychol Psychiatry 2010 Jul;51(7):850-6
  54. Impaired fetal growth decreases the risk of childhood atopic eczema: a Swedish twin study.
    Lundholm C, Ortqvist A, Lichtenstein P, Cnattingius S, Almqvist C
    Clin. Exp. Allergy 2010 Jul;40(7):1044-53
  55. The genetics of autism spectrum disorders and related neuropsychiatric disorders in childhood.
    Lichtenstein P, Carlström E, Råstam M, Gillberg C, Anckarsäter H
    Am J Psychiatry 2010 Nov;167(11):1357-63
  56. The autism--tics, AD/HD and other comorbidities inventory (A-TAC): further validation of a telephone interview for epidemiological research.
    Larson T, Anckarsäter H, Gillberg C, Ståhlberg O, Carlström E, Kadesjö B, et al
    BMC Psychiatry 2010 Jan;10():1
  57. The Swedish version of the parent-rated Junior Temperament and Character Inventory (J-TCI).
    Kerekes N, Brändström S, Ståhlberg O, Larson T, Carlström E, Lichtenstein P, et al
    Psychol Rep 2010 Dec;107(3):715-25
  58. The Autism--Tics, AD/HD and other Comorbidities (A-TAC) telephone interview: convergence with the Child Behavior Checklist (CBCL).
    Halleröd S, Larson T, Ståhlberg O, Carlström E, Gillberg C, Anckarsäter H, et al
    Nord J Psychiatry 2010 May;64(3):218-24
  59. Does quantity have a quality all its own? Cumulative adversity and up- and down-regulation of circadian salivary cortisol levels in healthy children.
    Gustafsson P, Anckarsäter H, Lichtenstein P, Nelson N, Gustafsson P
    Psychoneuroendocrinology 2010 Oct;35(9):1410-5
  60. Familial factors do not confound the association between birth weight and childhood asthma.
    Ortqvist A, Lundholm C, Carlström E, Lichtenstein P, Cnattingius S, Almqvist C
    Pediatrics 2009 Oct;124(4):e737-43
  61. Anckarsater H, Larson T, Hansson SL, Carlstrom E, Stahlberg O, Gillberg C, Rastam M, Gillberg C, Lichtenstein P. Child Neurodevelopmental and Behavioural Problems are Intercorrelated and Dimensionally Distributed in the General Population. The Open Psychiatry Journal 2008;2:5-11.   
  62. The Swedish Twin Registry in the third millennium: an update.
    Lichtenstein P, Sullivan P, Cnattingius S, Gatz M, Johansson S, Carlström E, et al
    Twin Res Hum Genet 2006 Dec;9(6):875-82
Twin research