The CATS study is a new and unique longitudinal study of children in metropolitan Melbourne as they approach adolescence. The study began in 2012 and will follow over 1200 children from grade 3 (8-9 years of age). The children will be visited once every year; in 2021 we completed the tenth wave of visits to participating students. The study will also collect information on parents and teachers. The main focus of the study is on the health and emotional development of children during the middle years of school with the aim of improving our understanding of the many influences that affect the health and emotional adjustment of children as they approach their teens. The study will look at the experiences of children and their families, their changing social context as they move into secondary school and their reactions to the biological changes of puberty. The information collected as part of this large study will help us identify when and how to promote the best health and emotional adjustment in pre-teens.

For information on the imaging component of CATS, please go to the Imaging Brain Development of CATS listing.


Study name Childhood to Adolescence Transition Study
Study abbreviation CATS
Current principal investigator/s

Professor George Patton

Current project manager Paul Hockey
Cohort representative (study contact) Paul Hockey
Postal address CATS Study, Murdoch Childrens Research Institute, The Royal Children’s Hospital, Flemington Road, Parkville VIC 3052, Australia
Phone +61 3 9345 3732

Primary Institution Murdoch Children’s Research Institute
Collaborating Institution/s University of Melbourne
University of South Australia
University of NSW
UCL Institute of Child Health, UK
La Trobe University, Australia
Deakin University, Geelong
University of Washington, Seattle USA
University of Birmingham, UK
University of Oregon, USA
Major funding sources Murdoch Children’s Research Institute, Royal Children’s Hospital, National Health and Medical Research Council, Department of Education and Training, Australian Rotary Health Research Fund, The Invergowrie Foundation 
Study website
Key reference Mundy, L.K., Simmons, J.G., Allen, N.B., Viner, R.M., Bayer, J.K., Olds, T., Williams, J., Olsson, C., Romaniuk, H., Mensah, F., Sawyer, S.M., Degenhardt, L., Alati, R., Wake, M., Jacka, F. and Patton, G.C.. Study protocol: the Childhood to Adolescence Transition Study (CATS). BMC Pediatr. 2013 Oct 8;13:160. doi: 10.1186/1471-2431-13-160
Are data available to others outside study team? Yes, through study publication protocol coordinated by project manager.
Study focus The effect of puberty on health and emotional development.
Sampling frame All Grade 3 students (8-9 years of age) from a stratified cluster sample of schools in Melbourne, Australia were invited to take part.
Year commenced 2012
Commencement sample 1239
Intergenerational? No 
Imaging MRI, fMRI on iCATS nested study (n=128)
Linkage NAPLAN (Victorian Curriculum and Assessment Authority)
Biosamples? Saliva (8-9 years, 10-11 years, 11-12 years, 16-17 years)
Ethics approvals or requirements? This project only (Specific consent)
Future research related to this project (Extended consent)


Wave Year Age (mean, range) Eligible sample
1 2012 8.5 (8 – 11) years 1239
2 2013 9.9 (8.8 – 11.5) years 1158
3 2014 10.9 (9.8 – 12.7) years 1119
4 2015 11.9 (10.7 – 13.5) years 1066
5 2016 13.0 (11.6 – 14.6) years 1175 (substudy 110)
6 2017 13 – 14 years 1177
7 2018 14 – 15 years 1137
8 2019 15 – 16 years 1102
9 2020 16 – 17 years 1084
9 2021 17 – 18 years TBC
10 2022 18 – 19 years TBC