In infancy and early childhood, mental health refers to "the capacity to experience, regulate, and express emotions; form close and secure interpersonal relationships; and explore the environment and learn" (J. Osofsky, statement before Congressional Committee, 2004). The development of these capacities during the child's first three years or the failure to do so lays a foundation that affects the rest of the child's life.

In our wishful thinking we might imagine that infants are too young to have problems with mental health. However, infants can have challenges arising from neurological and other medical conditions, as well as from the stresses and difficulties in their environments (and these two kinds of challenges are often interwoven together).

In recent years, infant mental health has emerged as a professional discipline concerned with promoting mental health capacities in the child and family, recognizing challenges when they occur, and developing strategies to address those challenges.