Book excerpt: The “spectrum in this disorder is Autistic Disorder, Asperger Syndrome, and Pervasive Developmental Disorder. This issue specifically addresses acute management of the extreme behaviors that accompany this disorder spectrum: extreme behaviors, complete lack of communication, inability to learn or express language, etc, and covers in-hospital or residential therapies as well as in-home family involvement. Medical treatment for this disorder is the main focus of discussion in topics such as: Emotional Regulation: Concepts and Practice in ASD; Specialized Inpatient Treatment of ASD; Residential Treatment of Severe Behavioral Disturbance in ASD; Treatment of ASD in General Child Psychiatry Units; Behavioral Approaches to Acute Problems; Communication Strategies for Behavioral Challenges in ASD, along with topics covering Psychiatric Assessment of Acute Presentations in ASD; Sensory Regulation and its Relationship to Acute Problems in ASD; Family Dysfunction, Assessment and Treatment in the context of Severe Behavioral Disturbance in ASD; and Self Injurious Behavior in ASD.