Infant and early childhood mental health is the developing capacity of the child from birth to 5 years old to form close and secure adult and peer relationships; experience, manage, and express a full range of emotions; and explore the environment and learn—all in the context of family, community, and culture. Infant and early childhood mental health is also a term used to describe the full continuum of services and supports (i.e., promotion, prevention, and treatment) necessary to promote healthy development, prevent mental health problems, and treat mental health disorders.