Results

Pervasive Developmental Disorders (PDD) as defined in the American Psychiatric Association’s Diagnostic and Statistical Manual of Mental Disorders – Fourth Edition (DSM-IV) is a category of disorders incorporating extreme developmental abnormalities with onset in the first three years of life. Pervasive Developmental Disorder represents a distortion in basic development with characteristic features including:

• Severe and pervasive impairment in reciprocal social interaction.
• Severe and pervasive impairment in communication skills.
• Presence of stereotyped behavior, interests and activities.

Within the board classification of PDD are five subtypes: Autistic Disorder, Asperger’s Disorder, Rett’s Disorder, Childhood Disintegrative Disorder and PDD – not otherwise specified (PDD-NOS).

Autism is characterized by impairment in social interaction in at least two ways; impairment in communication in at least one way; and restricted, repetitive and stereotypical patterns of behavior, interest and activities in at least one way (DSM-IV, 1994).

Asperger’s Disorder is characterized by severe and sustained impairment in social interaction combined with restricted, repetitive ad stereotyped patterns of behavior, interest and activities (DSM-IV, 1994).

Rett’s Disorder is the only subtype of PDD which occurs exclusively in females. In this disorder, development seems normal through the first five months of life, followed by deceleration of head growth, loss of previously acquired purposeful hand skills with subsequent development of stereotyped hand movements, loss of social engagement, appearance of poorly coordinated gait or trunk movements, and severely impaired expressive and receptive language (DSM-IV, 1994).

Childhood Disintegrative Disorder is characterized by development that appears normal through the first two years of life. Following this, abnormalities develop in at least two of the following areas: social interaction, communication, and restricted, repetitive, stereotyped patterns of behavior, interests and activities. In addition, there is clinically significant loss of previously acquired skills (before age 10), in at least two of the following areas: expressive or representative language, social skills or adaptive behavior, bowel or bladder control, play and motor skills (DSM-IV, 1994).

The category of PDD_NOS is used when there is severe and pervasive impairment in the development of reciprocal social interaction and verbal and nonverbal communication skills, or when stereotyped behavior, interest and activities are present, but symptoms do not meet the criteria for other disorders (DSM-IV, 1994).