Sex differences in autism

Autism Spectrum Disorders (ASD) are currently more commonly diagnosed in males, with a ratio of about 1 female for every 4 males diagnosed.[1] Currently, one in every 189 females and one in 42 males is diagnosed with Autism Spectrum Disorder (ASD).[2] There is some evidence that females may also receive diagnoses somewhat later than males, however thus far results have been contradictory.[3] Researchers have also debated whether a diagnostic gender bias has played a role in females being under diagnosed with Autism Spectrum Disorder.[4] Researchers have speculated a gender bias in the parental reporting due to the expectations and socialization of gender roles in society.[5] As of yet, there have been no studies specifically addressing the occurrence of autism in intersex individuals, and this is an area that requires further research. Several theories exist to explain the male-female sex based discrepancy, such as a genetic protective effect,[6][7][8] the Extreme Male Brain Theory,[9][10] and phenotypic differences in the presentation between sexes.[8][11][12][13]

Summary

Differences in presentation of autistic traits are widely supported within the autistic community, and gaining support in the professional field. Hans Asperger was one of the first people to study autism, yet all of his four students were male. Another early researcher, Leo Kanner described "autistic disturbances of affective contact" in the group consisting of eight boys and three girls.[14] Since biological differences exist between males and females, it follows that the presentation of autism would differ as well. Recent studies suggest this to be true, with evidence of increased incidence of social anxiety,[12] anorexia nervosa,[15][16] and self-harm in autistic females.[17]

Female protective effect hypothesis

According to a female protective effect hypothesis more extreme genetic mutations are required for a girl to develop autism than for a boy. In 2012, Harvard researchers published findings suggesting that, on average, more genetic and environmental risk factors are required for girls to develop autism, compared to boys. The researchers analyzed DNA samples of nearly 800 families affected by autism and nearly 16,000 individuals with a variety of neurodevelopmental disorders. They looked for various types of gene mutations. Overall, they found that females diagnosed with autism or another neurodevelopmental disorder had a greater number of harmful mutations throughout the genome than did males with the same disorders.[18]

Sexuality and gender variance

Sexuality is often discussed within the autistic community, with many observations that identities other than cis-hetero seem to be more common than is observed in the neurotypical population. There have not been many formal studies on this to date, however members of the community speculate that autistic individuals generally have different ideals, perceptions, and desires than neurotypicals, or simply do not comprehend or agree with society's expectation, making them more apt to diverge from the norm.

Sexual orientation

In an ongoing study conducted at the University of Massachusetts Boston found autistic participants to more often identify as something other than heterosexual compared to an allistic (non-autistic) control group (92% and 72% respectively).[19] The study also found autistic individuals to be more likely to identify as asexual (37% ASD vs 22% NT).

Gender identity

In the same study, preliminary results demonstrate that female-assigned individuals on the autistic spectrum are much more likely to identify with trans, fluid, or non-binary gender identities than allistic counterparts, with 50% of autistic participants reporting a gender other than that which they were assigned at birth versus only 22% of the control group.[19]

Another study looking at the co-occurrence of ASD in patients with gender dysphoria found 7.8% of patients to be on the autism spectrum.[20] This is much higher than the estimated 1% of people with ASD in the general population, suggesting a link between autism and gender variance.

Sexual satisfaction

A study conducted by Byers and Nichols (2014), explored the level of sexual satisfaction of high functioning autistic individuals. The researchers tested the sexual and relationship satisfaction of neurotypical individuals versus high functioning autistic individuals. The results suggest that men with ASD are generally less satisfied with their relationship or marriage compared to neurotypical men and women, and women with ASD.[21]

Hypothesis of female underdiagnosis

Some authors, clinicians and experts like Judith Gould, Tony Attwood, Lorna Wing and Christopher Gillberg[22] have proposed that autism in females may be underdiagnosed due to supposed better natural superficial social mimicry skills in females, partially different set of symptoms and worse knowledge about autism in females among experts.[23] In his preword to the book Asperger's and Girls Tony Attwood writes: "These tentative explanations for the apparent underrepresentation of girls with Asperger's Syndrome have yet to be examined by objective research studies."[24]

Specifically Judith Gould has discussed the idea that a pervasive developmental disorder called pathological demand avoidance, which is not officially included in diagnostic manuals may offer a glimpse about how autism in females may present in some cases.[25]

References

  1. ↑ Fombonne, E. (2009). Epidemiology of pervasive developmental disorders. Pediatric Research, 65(6), 591–598. http://doi.org/10.1203/PDR.0b013e31819e7203
  2. ↑ http://www.cdc.gov/ncbddd/autism/data.html Autism Spectrum Disorder (ASD): Data & Statistics
  3. ↑ Begeer, S., Mandell, D., Wijnker-Holmes, B., Venderbosch, S., Rem, D., Stekelenburg, F., & Koot, H. M. (2013). Sex Differences in the Timing of Identification Among Children and Adults with Autism Spectrum Disorders. Journal of Autism and Developmental Disorders, 43, 1151–1156. http://doi.org/10.1007/s10803-012-1656-z
  4. ↑ Supekar, Kaustubh; Menon, Vinod (2015-09-04). "Sex differences in structural organization of motor systems and their dissociable links with repetitive/restricted behaviors in children with autism". Molecular Autism. 6 (1). doi:10.1186/s13229-015-0042-z. PMC 4559968Freely accessible. PMID 26347127.
  5. ↑ Holtmann, Martin; Bölte, Sven; Poustka, Fritz (2007-05-01). "Autism spectrum disorders: sex differences in autistic behaviour domains and coexisting psychopathology". Developmental Medicine & Child Neurology. 49 (5): 361–366. doi:10.1111/j.1469-8749.2007.00361.x. ISSN 1469-8749.
  6. ↑ Gockley, J., Willsey, a J., Dong, S., Dougherty, J. D., Constantino, J. N., & Sanders, S. J. (2015). The female protective effect in autism spectrum disorder is not mediated by a single genetic locus. Molecular Autism, 6, 25. http://doi.org/10.1186/s13229-015-0014-3
  7. ↑ Robinson, E. B., Lichtenstein, P., Anckarsater, H., Happe, F., & Ronald, a. (2013). Examining and interpreting the female protective effect against autistic behavior. Proceedings of the National Academy of Sciences, 110(13), 5258–5262. http://doi.org/10.1073/pnas.1211070110
  8. 1 2 Lai, M.-C., Baron-Cohen, S., & Buxbaum, J. D. (2015). Understanding autism in the light of sex/gender. Molecular Autism, 6, 1–6. http://doi.org/10.1186/s13229-015-0021-4
  9. ↑ Baron-Cohen, S. (2002). The extreme male brain theory of autism. TRENDS in Cognitive Sciences, 6(6), 248–254. http://doi.org/10.1016/S1364-6613(02)01904-6
  10. ↑ Lai, M.-C., Lombardo, M. V., Pasco, G., Ruigrok, A. N. V, Wheelwright, S. J., Sadek, S. a., … Baron-Cohen, S. (2011). A Behavioral Comparison of Male and Female Adults with High Functioning Autism Spectrum Conditions. PLoS ONE, 6(6), e20835. http://doi.org/10.1371/journal.pone.0020835
  11. ↑ Lai, M.-C., Lombardo, M. V, Ruigrok, A. N. V, Chakrabarti, B., Wheelwright, S. J., Auyeung, B., … Baron-Cohen, S. (2012). Cognition in males and females with autism: similarities and differences. PloS One, 7(10), e47198. http://doi.org/10.1371/journal.pone.0047198
  12. 1 2 Ludlow, a. K., Roberts, H., & Gutierrez, R. (2015). Social Anxiety and Response to Touch: A Preliminary Exploration of Broader Autism Phenotype in Females. SAGE Open, 5, 2158244015580854–. http://doi.org/10.1177/2158244015580854
  13. ↑ Torres, E. B., Isenhower, R. W., Yanovich, P., Rehrig, G., Stigler, K., Nurnberger, J., & José, J. V. (2013). Strategies to develop putative biomarkers to characterize the female phenotype with autism spectrum disorders. Journal of Neurophysiology, 110, 1646–62. http://doi.org/10.1152/jn.00059.2013
  14. ↑ Kanner, L. (1943). Autistic disturbances of affective contact. Nervous Child, 2, 217-250.
  15. ↑ Baron-Cohen, S., Jaffa, T., Davies, S., Auyeung, B., Allison, C., & Wheelwright, S. (2013). Do girls with anorexia nervosa have elevated autistic traits? Molecular Autism, 4(1), 24. http://doi.org/10.1186/2040-2392-4-24
  16. ↑ Rhind, C., Bonfioli, E., Hibbs, R., Goddard, E., Macdonald, P., Gowers, S., … Treasure, J. (2014). An examination of autism spectrum traits in adolescents with anorexia nervosa and their parents. Molecular Autism, 5(1), 56. http://doi.org/10.1186/2040-2392-5-56
  17. ↑ Cohen, I. L., Tsiouris, J. A., Flory, M. J., Kim, S.-Y., Freedland, R., Heaney, G., … Brown, W. T. (2010). A Large Scale Study of the Psychometric Characteristics of the IBR Modified Overt Aggression Scale: Findings and Evidence for Increased Self-Destructive Behaviors in Adult Females with Autism Spectrum Disorder. J Autism Dev Disord, 40, 599–609.
  18. ↑ Jacquemont, S., Coe, B., Hersch, M., Duyzend, M., Krumm, N., Bergmann, S., Beckmann, J., Rosenfeld, J., Eichler, E. (2014) A Higher Mutational Burden in Females Supports a “Female Protective Model” in Neurodevelopmental Disorders. The American Society of Human Genetics, http://www.cell.com/ajhg/abstract/S0002-9297(14)00059-7
  19. 1 2 "Might be interesting to y'all: results from a study about autistic women and sexuality. | Kintsugi". Kintsugi.seebs.net. Retrieved 2015-10-19.
  20. ↑ De Vries, A. L. C., Noens, I. L. J., Cohen-Kettenis, P. T., van Berckelaer-Onnes, I. A., & Doreleijers, T. A. (2010). Autism Spectrum Disorders in Gender Dysphoric Children and Adolescents. J Autism Dev Disord, 40, 930–936. http://doi.org/10.1007/s10803-010-0935-9
  21. ↑ Byers, E (2014). "Sexual Satisfaction of High-Functioning Adults with Autism Spectrum Disorder". Sexuality and Disability Sex.
  22. ↑ "Gender and autism". The National Autistic Society. Retrieved 2016-06-01.
  23. ↑ Attwood, Tony (2006). Asperger's and Girls. London: Jessica Kingsley Publishers. pp. 2–6. ISBN 978-1932565409.
  24. ↑ Attwood, Tony (2006). Asperger's and Girls. London: Jessica Kingsley Publishers. p. 6. ISBN 978-1932565409.
  25. ↑ "Missed Diagnosis or Misdiagnosis? Women and Girls with PDA" (PDF). Dr Judith Gould, Dr Jacqui Ashton Smith. Retrieved 2016-01-06.
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