This is a group of uncommon psychiatric disorders with the common denominators of deficient social skills, impaired development of verbal and nonverbal communication, and an inability to participate in activities requiring imagination. The child may be slow in developing intellect, language and speech, and motor activity, including posture. The degree and form of these deficiencies vary widely among afflicted children. The most well-known pervasive developmental disorder is autism.
Several forms of pervasive developmental disorders have been identified: Autistic disorder, Rett's Disorder, childhood disintegrative disorder, asperger syndrome, and Pervasive Developmental Disorder not otherwise specified (PDD NOS). Overall, 30-60 children per 10,000 are affected. Most affected children have autism or PDD NOS. Except for Rett’s, all forms of PDD are more common in boys.
Autism happens by 30 months old. Some infants appear normal for the first year. Others may not be responsive to cuddling or eye contact with their mothers. Early differences in autistic children include that they prefer to play by themselves and often develop rituals and repetitive behaviors, including rocking and head-banging. Their play also tends to be repetitive, and they may spend hours lining up objects or being preoccupied in making patterns with toys. Creative play with dolls or stuffed animals is limited, as is play that requires interaction with others, such as pat-a-cake or peek-a-boo. They seem detached and unable to become involved emotionally with those around them. Autism may be accompanied by mental retardation and/or seizures.Rett's disorder involves autistic behavior, dementia, ataxia, severely impaired expressive and receptive language development with severe psychomotor retardation, and loss of previously acquired purposeful hand use between ages 30 months and 5 years, with the subsequent development of stereotyped hand movements (e.g., hand-wringing or hand washing). It is an x-linked genetic disorder, making it much more common in girls.
Childhood integrative disorder involves qualitative impairment in social interaction; qualitative impairments in communication; and restricted, repetitive, and stereotyped patterns of behavior, interests, and activities, including motor stereotypes and mannerisms. It starts later than autism and most children have normal development until 4 years old.
Asperger's disorder involves encompassing preoccupation with one or more stereotyped patterns of interest that is abnormal either in intensity or focus; apparent inflexible adherence to specific, non-functional routines or rituals; stereotyped and repetitive motor mannerisms; and persistent preoccupation with parts or objects. This disturbance causes clinically significant impairment in social, occupational, or other important areas of functioning. Asperger’s also starts later than autism, usually in the third year. Unlike the other forms of PDD, Asperger’s is usually associated with normal intelligence and sometimes with high intelligence.