The Child and Adolescent Twin Study in Sweden (CATSS)

Abstract

The Child and Adolescent Twin Study in Sweden (CATSS) is an ongoing longitudinal twin study targeting all twins born in Sweden since July 1, 1992. Since 2004, parents of twins are interviewed regarding the children's somatic and mental health and social environment in connection with their 9th or 12th birthdays (CATSS-9/12). By January 2010, 8,610 parental interviews concerning 17,220 twins had been completed, with an overall response rate of 80%. At age 15 (CATSS-15) and 18 (CATSS-18), twins and parents complete questionnaires that, in addition to assessments of somatic and mental health, include measures of personality development and psychosocial adaptation. Twin pairs in CATSS-9/12 with one or both twins screening positive for autism spectrum disorders, attention deficit/hyperactivity disorder, tic disorders, developmental coordination disorder, learning disorders, oppositional defiant disorder, conduct disorder, obsessive–compulsive disorder, and/or eating problems have been followed with in-depth questionnaires on family, social environment and personality, and subsequently by clinical assessments at age 15 together with randomly selected population controls, including 195 clinically assessed twin pairs from the first 2 year cohorts (CATSS-15/DOGSS). This article describes the cohorts and study groups, data collection, and measures used. Prevalences, distributions, heritability estimates, ages at onset, and sex differences of mental health problems in the CATSS-9/12, that were analyzed and found to be overall comparable to those of other clinical and epidemiological studies. The CATSS study has the potential of answering important questions on the etiology of childhood mental health problems and their role in the development of later adjustment problems.

Subthreshold and threshold attention deficit hyperactivity disorder symptoms in childhood: psychosocial outcomes in adolescence in boys and girls

“…Previous attrition analyses of differences between non‐responders and responders in the CATSS study, based on data from approximately 11 000 twins, have indicated that CATSS non‐responders more often belong to lower socioeconomic groups 47. Hypothetically, a family burdened with psychosocial problems may be less motivated to participate, which could explain some of the attrition.…”

“…The Child and Adolescent Twin Study in Sweden (CATSS) is an ongoing longitudinal cohort study following all twins born in Sweden from 1992 and onwards, that started in 2004 47. All twin parents in the country are invited to participate in a telephone interview.…”

“…Before July 2005, consenting parents were interviewed when the twins were 12 years old, and after that time point, parents were interviewed at twin‐age 9. The reason for choosing these age groups was that most of the major child psychiatric problem constellations have been established by this age, while the problems associated with puberty most often have not yet emerged 47. Including 12‐year‐olds during the first waves of data collection was a way of increasing the speed to the point in time at which follow‐ups of adolescents and young adults would be possible.…”

Heritability of Cortisol Regulation in Children

“…The study started in 2004 and the response rate of the telephone interview was 80% (Anckarsäter et al, 2011). Interviewers from a professional company carried out the interviews after a brief introduction in child and adolescent psychiatry and twin research.…”

Childhood neurodevelopmental problems and adolescent bully victimization: population-based, prospective twin study in Sweden

“…Past studies have demonstrated substantial overlap among specific NDPs (20,22,23,28), and Gillberg (38) has argued for more comprehensive assessment and treatment for children with NDPs than what the current diagnostic system allows. The current results might be seen as corroborating this argument, in that a general NDP factor appeared stronger in predicting bullying victimization than specific neurodevelopmental problems or diagnoses.…”