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.

CATSS is a part of several international projects where data from different countries is used to reach better and more convincing conclusions. This gives us the opportunity to compare how things are alike but also different in different countries.

One of the project is called ACTION and aims to investigate aggression. You can read more about this project on the separate website.

Project leader

Professor

Paul Lichtenstein

Phone: +46-(0)8-524 874 24
Organizational unit: Department of Medical Epidemiology and Biostatistics (MEB), C8
E-mail: Paul.Lichtenstein@ki.se

Contact

We are happy to answer your questions and can be reached by e-mail to catss@meb.ki.se

Project period: 2004-ongoing

Partners

Project staff

System developer

Camilla Palm

Phone: +46-(0)8-524 844 49
E-mail: camilla.palm@ki.se

System developer

Isabelle Kizling

Phone: +46-(0)8-524 823 07
Organizational unit: Department of Medical Epidemiology and Biostatistics (MEB), C8
E-mail: isabelle.kizling@ki.se

Assistant professor

Yi Lu

Organizational unit: Department of Medical Epidemiology and Biostatistics (MEB), C8
E-mail: lu.yi@ki.se

Postdoc

Mark Taylor

Phone: +46-(0)8-524 822 67
Organizational unit: Department of Medical Epidemiology and Biostatistics (MEB), C8
E-mail: mark.taylor@ki.se

Postdoc

Martin Cederlöf

Organizational unit: CPF Hellner
E-mail: martin.cederlof@ki.se

Assistant professor

Erik Pettersson

E-mail: erik.pettersson@ki.se

Published theses

Ongoing thesis work

Publications

Twin research