The use of expressive play therapy as a tool in helping children work through emotional issues dates all the way back to the time of Sigmund Freud in 1909 when he introduced this modality of treatment into his work with children.  Freud's theories were later expanded upon by his students, most notably his daughter, Anna, who systematized and expanded upon the use of play therapy as a legimate treatment modality when working with children.

During the first year of life, children form strong bonds with their parents and caregivers. You might not think that children are aware of much during that first year, but in reality they are forming very important bonds with people around them. These bonds will lead to an attachment style being adopted by the child; and, each child's individual attachment style will depend on the types of interaction he or she has with his or her caregivers.

Attention Deficit Hyperactivity Disorder, or ADHD as it is commonly called, is a disruptive behavior disorder that is characterized by a chronic pattern of inattention, hyperactivity, and poor impulse control or a combination of the three that affects how children, adolescents, or adults function in their day-to-day life.  ADHD is, technically, a childhood disorder and, if diagnosed in an adult, must have been evident during childhood.  Recent, emerging research from the National Institute of Mental Health suggests that ADHD

Childhood psychological disorders are broadly categorized into anxiety disorders, attachment disorders, pervasive developmental disorders, disruptive behavior disorders, and mood disorders.  Many of these disorders have strong genetic components, just like Autistic Disorder and Attention-Deficit Hyperactivity Disorder.  These genetically-linked disorders tend to be identified early in the life of a child.