caught up with some of the world's leading experts on the mental health of kids under the age of three at the Expanding Horizons for the Early Years conference, organized by the Infant Mental Health Promotion unit at the Hospital for Sick Children.

One of those experts was Deborah Weatherston, the executive director of the Michigan Association for Infant Mental Health, who gave a talk called, Growth and Change in a Rapidly Changing World.

In the videos below, she answers our questions about child mental health, beginning with the question, "What are the biggest mental health problems faced by children under the age of three?"