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Effective Nov. 1, 2023, clients and families, visitors, vendors and staff are required to wear a mask while moving throughout the hospital, including while in elevators, in spaces where clients receive care or participate in research. A medical grade mask will be available upon entry.


Jonathan Leef

Jonathan works as a Clinical Research Coordinator in the Autism Research Centre. Currently, he focuses on coordinating several projects related to the longitudinal Infant Sibling Study, including the Proband and NeuroDevNet studies, as well as the 5- and 8-year visits. The Proband and NueroDevNet projects both involve studying the relationships between the behavioural and genetic characteristics of children with ASD and those of their younger siblings participating in the Infant Sibling Study. The 5- and 8-year visits refer to the follow-up assessments completed with the infant siblings once they reach 5 and 8 years of age.

Jonathan has been working with children and adolescents with ASD and their parents since 2001, in both research and clinical capacities. He facilitated social-skills and parent groups at the Centre for Addiction and Mental Health (CAMH) for many years, and worked as a research assistant at the Hospital for Sick Children’s Autism Research Unit before moving into his current position at the Autism Research Centre.

He earned a Bachelor of Science in Psychology and History, a Master of Arts in Developmental Psychology and Developmental Science, and is currently a Ph.D. candidate in School and Clinical Child Psychology at the University of Toronto (OISE/UT). His research interests have included children’s theory-of-mind, language and social-cognitive development, while his current research focuses on the gender-identity development of children with ASD.