INCIDENCE OF ASPERGER'S
Prevalence estimates vary enormously. A 2003
review of epidemiological studies found prevalence rates ranging
from 0.03 to 4.84 per 1,000, with the ratio of autism to Asperger
syndrome averaging 5:1; combining this with a conservative prevalence
estimate for autism of 1.3 per 1,000 suggests indirectly that the
prevalence of Aspergers syndrome might be around 0.26 per 1,000.
Part of the variance in estimates arises from differences in diagnostic
criteria. For example, a relatively small 2007 study of 5,484 eight-year-old
children in Finland found 2.9 children per 1,000 met the ICD-10
criteria for an Aspergers syndrome diagnosis
, 2.7 per 1,000 for Gillberg and Gillberg criteria, 2.5 for DSM-IV,
1.6 for Szatmari et al., and 4.3 per 1,000 for the union of the
four criteria. Boys seem to be at higher risk for Aspergers syndrome
than girls; estimates of the sex ratio range from 1.6:1 to 4:1,
using the Gillberg and Gillberg criteria.
Anxiety and depression are the most common other
conditions seen at the same time; comorbidity of these in persons
with Aspergers syndrome is estimated at 65%. Depression is common
in adolescents and adults; children are likely to present with ADHD.
Reports have associated Aspergers syndrome with medical conditions
such as aminoaciduria and ligamentous laxity, but these have been
case reports or small studies and no factors have been associated
with Aspergers syndrome across studies. One study of males with
Aspergers syndrome found an increased rate of epilepsy
and a high rate (51%) of nonverbal learning disability. Aspergers
syndrome is associated with tics, Tourette
syndrome, and bipolar
disorder, and the repetitive
behaviors of Aspergers syndrome have many similarities with
the symptoms of obsessive
compulsive disorder and obsessive-compulsive
More males diagnosed with Asperger's than females
Like other Autism Spectrum Disorders, Aspergers
syndrome prevalence estimates for males are higher than for females,
but some clinicians believe that this may not reflect the actual
incidence rates. Tony Attwood suggests that females learn to better
compensate for their impairments due to gender differences in the
handling of socialization. The Ehlers and Gillberg study found a
4:1 male to female ratio in subjects meeting Gillberg’s criteria
for Aspergers syndrome, but a lower 2.3:1 ratio when suspected or
borderline cases were included.
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children with autism spectrum disorders". Pediatrics 116
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– press release (2005-07-05).
61.Chiang HM, Lin YH (2007). "Mathematical ability of students
with Asperger syndrome and high-functioning autism". Autism
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62. Herera S. "Mild autism has 'selective advantages'",
CNBC, 2005-02-25. Retrieved on 2007-11-14.
63. Moran M (2006). "Asperger's may be answer to diagnostic
mysteries". Psychiatr News 41 (19): 21.
64. Fombonne E, Tidmarsh L (2003). "Epidemiologic data on Asperger
disorder". Child Adolesc Psychiatr Clin N Am 12 (1): 15–21.
65. Fombonne E (2007). "Epidemiological surveys of pervasive
developmental disorders", in Volkmar FR: Autism and Pervasive
Developmental Disorders, 2nd ed, Cambridge University Press, 33–68.
66. Mattila ML, Kielinen M, Jussila K et al. (2007). "An epidemiological
and diagnostic study of Asperger syndrome according to four sets
of diagnostic criteria". J Am Acad Child Adolesc Psychiatry
46 (5): 636–46. doi:10.1097/chi.0b013e318033ff42. PMID 17450055.
67. Ghaziuddin M, Weidmer-Mikhail E, Ghaziuddin N (1998). "Comorbidity
of Asperger syndrome: a preliminary report". J Intellect Disabil
Res 42 (4): 279–83. PMID 9786442.
68. ^ Cederlund M, Gillberg C (2004). "One hundred males with
Asperger syndrome: a clinical study of background and associated
factors". Dev Med Child Neurol 46 (10): 652–60. doi:10.1111/j.1469-8749.2004.tb00977.x.
69. Gillberg C, Billstedt E (2000). "Autism and Asperger syndrome:
coexistence with other clinical disorders". Acta Psychiatr
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