Pervasive developmental disorders, or autism spectrum disorders, include a category of conditions characterized by difficulties with language, cognition and social skills, according to the American Psychiatric Association. The disorders included under the category of pervasive developmental disorders are autism, Asperger's disorder, Rett's disorder, childhood disintegrative disorder and pervasive developmental disorder not otherwise specified. PDD-NOS is often used for pervasive developmental disorder not otherwise specified, given the lengthy title of the condition.
Clinical Description
Individuals with pervasive developmental disorders, have unusual or impaired social, communication, motor and cognitive abilities. People with autism have impaired social skills, such as not making eye contact with others. About 50 percent of individuals with autism never acquire constructive speech, according to a study in the 1994 issue of the American Journal of Psychiatry. Those who can speak often repeat the speech of others or have difficulty carrying on a conversation. People with autism also display repetitive actions, ritualistic behaviors or have an intense interest. Individuals with Asperger's disorder also experience difficulty with social interaction, repetitive movements and restricted interests, but language skills are typically fine. Children with Rett's disorder seem to stop developing after a seemingly healthy start in development. They often display hand wringing and may have declines in motor skills, intellectual functioning and communication skills. Childhood disintegrative disorder also begins to develop in early childhood after a period of normal childhood development. The condition is characterized by severe deterioration in language and motor skills. People with PDD-NOS have some of the symptoms of autism, but the diagnostic criteria of autism or Asperger's disorder are not met.
Prevalence
About 6 in 1,000 children have a pervasive developmental disorder, according to a study in the January 30, 2007 issue of "Neurology." Four times as many males have pervasive developmental disorder than females. Regarding specific disorders, per 10,000 children, about 17 have autism, 8 have Asperger's disorder, 36 have PDD-NOS and less than 1 have Rett's disorder or childhood disintegrative disorder, as found in a study in the June 27, 2001 edition of the "Journal of the American Medical Association".
Onset
For a diagnosis of autism, symptoms appear before the age of 3, according to the American Psychological Association. Asperger's disorder is usually recognized later than autism, as most children are diagnosed between the ages of 5 and 9 years. After an apparently normal start in childhood development, the developmental decline of Rett's disorder typically begins to occur between the ages of 3 months and 3 years and the decline of childhood disintegration disorder begin between the ages of 2 to 4 years.
Causes
According to the National Institute of Neurological Disorders and Stroke, researchers have identified several genes linked to pervasive developmental disorders and found that individuals with pervasive developmental disorders have some atypical brain structures and irregular levels of biochemicals in the brain. These findings indicate a biological basis, but researchers also believe environmental factors may interact with genes to develop pervasive developmental disorders. Researchers are investigating the specific causal mechanisms.
Treatment
Treatment of pervasive developmental disorders usually includes a team of specialists, including psychologists, speech therapists, and occupational therapists, to help reduce problematic behaviors, improve communication, social and motor skills, and to help the individual and families cope. Medications may be prescribed for concurrent conditions as anxiety or attention deficit hyperactivity disorder.
References
- "American Journal of Psychiatry"; Field Trial for Autistic Disorder in DSM-IV. Fred Volkmar, Ami Klin, Bryna Siegel, Peter Szatmari, Catherine Lord, Magda Campbell, B.J. Freeman, Domenic Cichetti, Michael Rutter, William Kline, Jan Buitelaar, Yossie Hattab, Eric Fombonne, Joaquin Fuentes, John Werry, Wendy Stone, J. Kerbeshian, Yoshihiko Hoshino, Joel Bregman, Katherine Loveland, Ludwig Szymanski, and Kenneth Towbin. 1994.
- National Institute of Neurological Disorders and Stroke: Autism Fact Sheet
- "Diagnostic and Statistical Manual of Mental Disorders (4th ed. Text Revision)"; American Psychiatric Association; 2002.
