CATSS overview:

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 birthday (CATSS9). At age 15 (CATSS15) and 18 (CATSS18), twins and parents complete questionnaires that, in addition to assessments of somatic and mental health, include measures of personality development and psychosocial adaptation. At the age of 24 (CATSS24) only twins participate in a web survey that mainly focuses on mental health.

CATSS24:

CATSS24 started in 2016. The study includes all 24-year-old twins, regardless of whether they participated in earlier CATSS-studies or not. The sample consists of both identical (monozygotic) and fraternal (dizygotic) twins, including same-sex and opposite-sex pairs. The total number of twins participating in CATSS24 is currently 11,600 out of 21,900 invited (December 2024). The response rate is 53%. Participants who have not already provided a DNA sample via saliva are requested to do so again. The saliva sample is used for zygosity determination and genotyping. The number of genotyped twins in CATSS24 is currently 7,300 (December 2024).

The question areas in the CATSS24 survey are listed below. For detailed information about variables, visit strdata.se.

AUDIT - Alcohol Use Disorders Identification Test
CES-D - Center for Epidemiologic Studies Depression Scale
DUDIT - Drug Use Disorders Identification Test
DCQ - Dysmorphic Concerns Questionnaire
HADS - Hospital Anxiety and Depression Scale
HRS-I - Hoarding Rating Scale-Interview
LHA - Life History of Aggression
OCI-R - Obsessive-Compulsive Inventory-Revised
PLE - Psychotic-like Experiences
EDI-2 - Eating Disorder Inventory-2
Zygosity
Premenstrual syndrome
Suicidal thoughts/attempts
Asthma and allergies
FFQ2020 - Food Frequency Questionnaire (updated version) Show less..

Data contains personal data

Yes

Sensitive personal data

Yes

Type of personal data

Pseudonymised, health data, social security number, lifestyle, exposures, names, addresses, survey responses

Code key exists

Yes

Language

English

Swedish

Method and outcome

Unit of analysis

Individual/Patient

Population

24-year old twins born in Sweden on or after 1st July, 1992

Time Method

Cross-section

Longitudinal: Cohort/Event-based

Study design

Cohort study

Description of study design

Data collection is conducted through a web survey. Until the end of 2020, participants had the possibility to choose a paper survey if they wished. Participation in the study is based on informed consent.

Sampling procedure

Total universe/Complete enumeration

All 24-year-old twins born in Sweden on or after 1st July 1992, according to the Medical Birth Registry (the National Board of Health and Welfare) and living in Sweden at the time of study invitation. Twins who have declined further participation in the twin registry, have protected identity, have emigrated, or died are excluded. Only complete twin pairs are invited to participate. Data from whole twin pairs and single twins are collected.

Time period(s) investigated

2016-11 – Ongoing

Biobank is connected to the study

The study has collected samples/material which are stored in a scientific collection or biobank

Scientific collection or biobank name: KI Biobank

Type(s) of sample: DNA from saliva

Number of individuals/objects

11600

Response rate/participation rate

53%

The total number of participating twins is 11,600 out of 21,900 invited (December 2024), resulting in a response rate of 53%.

Data format / data structure

Numeric

Text

Data collection

Mode of collection: Self-administered questionnaire
Description of the mode of collection: Paper or web questionnaire
Time period(s) for data collection: 2016-11–ongoing
Data collector: Karolinska Institutet
Instrument: LHA (Structured questionnaire)
LHA (Life History of Aggression) is a widely used instrument which aims to measure trait aggression and antiscocial behavior. LHA consists of 11 items divided into three subscales: agression, self-directed aggression and consequences/antisocial behavior.
DOI: 10.1016/s0165-1781(97)00119-4
Instrument: Suicide (Structured questionnaire)
Six questions to assess the prevalence of sucidal thoughts and attempted suicide.
DOI: 10.1176/ajp.149.1.41
Instrument: CESD (Structured questionnaire)
The Center for Epidemiologic Studies Depression Scale Revised (CESD-R) is used to rate how often respondents have experienced symptoms associated with depression over the past week, such as restless sleep, poor appetite, and loneliness.
DOI: 10.1016/j.psychres.2010.08.018
Instrument: HADS (Structured questionnaire)
Hospital Anxiety and Depression Scale (HADS) is a self-report questionnaire designed to measure anxiety and depression in patients within somatic care. The scale is used to assess and/or detect changes in anxiety and depressive symptoms in patients outside psychiatric care.
DOI: 10.1111/j.1600-0447.1983.tb09716.x
Instrument: DCQ (Structured questionnaire)
Dysmorphic Concerns Questionnaire (DCQ) is a self-report questionnaire consisting of seven items designed to assess cognitive and behavioral aspects of dysmorphic disorder. It has been validated as a screening tool for body dysmorphic disorder (BDD).
DOI: 10.3109/00048679809062719
DOI: 10.1046/j.1440-1614.2001.00860.x
DOI: 10.3109/00048671003596055
Instrument: EDI-2 (Structured questionnaire)
The Eating Disorder Inventory (EDI) is a self-report questionnaire used to assess the presence of eating disorders.
DOI:10.1002/1098-108X(198321)2:23.0.CO;2-6
DOI: 10.1080/08039480500504537
Instrument: HRSI
Hoarding Rating Scale-Interview (HRS-I) is a five-item semi-structured interview that assesses the features of compulsive hoarding (clutter, difficulty discarding, acquisition, distress and impairment).
DOI: 10.1016/j.psychres.2009.05.001
Instrument: OCI-R (Structured questionnaire)
The Obsessive–Compulsive Inventory (OCI) is a self-report measure for assessing symptoms of obsessive–compulsive disorder (OCD). In this questionnaire a shortened version is used, OCI-R.
DOI.10.1037/1040-3590.14.4.485
Instrument: PLE (Structured questionnaire)
Psychotic like experiences (PLE) - eight items adapted from the Diagnostic Interview Schedule for Children (DIS-C) to screen for psychotic-like experiences.
DOI:10.1016/j.schres.2006.11.006
Instrument: AUDIT (Structured questionnaire)
Alcohol Use Disorders Identification Test (AUDIT) is an instrument used to identify risky and harmful alcohol consumption. The instrument was originally developed by the World Health Organization (WHO).
DOI: 10.15288/jsa.1995.56.423
DOI: 10.1093/alcalc/37.3.245
DOI:10.1111/j.1530-0277.1997.tb03811.x
DOI: 10.1111/j.1360-0443.1993.tb02093.x
Instrument: DUDIT (Structured questionnaire)
Drug Use Disorders Identification Test (DUDIT) is an 11-item self-administered screening instrument for drug-related problems, giving information on the level of drug intake and selected criteria for substance abuse/harmful use and dependence according to the ICD-10 and DSM-4 diagnostic systems.
DOI: 10.1159/000081413
Instrument: FFQ2020 (Structured questionnaire)
An updated version of the Food Frequency Questionnaire (FFQ), used to monitor dietary habits.
DOI: 10.1186/s12937-024-00984-8
Source of the data: Registers/Records/Accounts: Medical/Clinical, Registers/Records/Accounts

Geographic coverage

Geographic spread

Geographic location: Sweden

Geographic description: Nationwide

Lowest geographic unit

Parish

Highest geographic unit

Country

Administrative information

Responsible department/unit

Department of Medical Epidemiology and Biostatistics

Funding 1

Funding agency: Karolinska Institutet

Funding 2

Funding agency: The Swedish Research Council
Funding information: Grant numbers: 2017-00641, 2023-00180

Ethics Review

Stockholm - Ref. 2015/1947-31/4

Ethics application approved on 21st of December 2015

Topic and keywords

Research area

Drug abuse, alcohol and smoking (CESSDA Topic Classification)

Youth (CESSDA Topic Classification)

Medical and health sciences (Standard för svensk indelning av forskningsämnen 2011)

Public health, global health, social medicine and epidemiology (Standard för svensk indelning av forskningsämnen 2011)

Reproductive health (CESSDA Topic Classification)

Health (CESSDA Topic Classification)

General health and well-being (CESSDA Topic Classification)

Medication and treatment (CESSDA Topic Classification)

Diet and nutrition (CESSDA Topic Classification)

Specific diseases, disorders and medical conditions (CESSDA Topic Classification)

Social behaviour and attitudes (CESSDA Topic Classification)

Social conditions and indicators (CESSDA Topic Classification)

Psychology (CESSDA Topic Classification)

Keywords

Phenotype, Genetics, Genotype, Twins, Twins, dizygotic, Twins, monozygotic, Gene-environment interaction, Environmental effects, Health, Zygosity

Publications

Anckarsäter H, Lundström S, Kollberg L, Kerekes N, Palm C, Carlström E, Långström N, Magnusson PK, Halldner L, Bölte S, Gillberg C, Gumpert C, Råstam M, Lichtenstein P. The Child and Adolescent Twin Study in Sweden (CATSS).
Twin Res Hum Genet. 2011 Dec;14(6):495-508.
DOI: https://doi.org/10.1375/twin.14.6.495