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The Lancet article, a case-series of n=12, that ignited the controversy over MMR vaccines and autism. It had been retracted by the journal and most of the authors


Joint attention refers to a series of skills that involve sharing of interest or focus on a particular object between a parent and a child. Some important examples of joint attention include:

  • protoimperative pointing or pointing to a desired object out of reach with the intent to get it (e.g., Mommy, I want that! <looking AND pointing to a toy>)
  • protodeclarative pointing or pointing to express or share an interest in in an object without the need to get it (e.g. Mommy, look there, a red bird! <looking AND pointing at a bird>)
  • gaze monitoring is noticing that a parent is looking at something and looking there too.


  • Prevalence of autism spectrum disorders (ASDs) is roughly 1 in 100 (63-116 per 10,000).
  • The Autism and Developmental Disabilities Monitoring (ADDM) Network estimates the prevalence of ASD in American 8-year-olds to be 1 in 68. (survey year 2010)
    • this was a significant increase compared to 2002 surveillance year (prevalence 1 in 150) with greatest increase among Hispanic children, non-Hispanic black children.
    • the proportion of children with ASD and co-occurring intellectual disability has steadily decreased from 47% in 2002, to 41% in 2006, to 31% in 2010.
  • Epilepsy has long been associated with autism, but estimates of prevalence of seizure disorder vary from 5% to 44%.
  • Associated conditions include tuberous sclerosis (2% of ASD patients), 15q deletions or duplications (2-3%), Fragile X syndrome, fetal alscohol syndrome, and Rett syndrome.

Risk Factors

Established risk factors

  • Valproate therapy during pregnancy or related folic acid deficiency
  • Taking SSRI's during pregnancy and up to 3 months before conception (up to 1 year before delivery) doubles the risk of ASD in the offspring;
    • risk is even higher (adjusted OR=3.8) if the expecting mother is taking SSRIs during the first trimester. (1)
  • Advanced maternal age is associated with increased risk in autism (SandinS, JAACAP 2012)
    • In this metaanalysis of 16 studies, relative risk (RR) of having a child with ASD was decreased (0.76) in younger women (<20 y.o. vs. 25-29) and increased (RR=1.31) in women >35y.o.
  • Advanced paternal age is likewise a risk factor.
    • in large Swedish study, risk increased two-fold for fathers >49yo, and four-fold for fathers 55 and older;(3) meta-analysis of 12 studies (presented in the same study) corroborated those findings.
  • Recurrence risk is about 5% (likelihood of a younger sibling also having autism), and as high as 20% in some studies.
    • monozygotic twin studies reveal concordance rate of 36-96%.
  • Interpregnancy interval extremes: having a second baby in under 2 years of the first, or waiting more than 5 years increased the risk of ASD with OR=1.5 and 1.28 respectively. (Cheslack-Pastava JAACAP 2014; 53:10)

Tentative risk factors

  • Influenza during pregnancy, prolonged fever, and use of macrolide antibiotics have been "cautiously" associated with increased risk for ASD in the offspring. (5)

Refuted risk factors

  • MMR vaccine had been shown to have no association with development of ASD.
    • The Lancet case-series of 12 children that suggested the association had been retracted.
  • Thimerosal, a mercury-containing anti-fungal preservative had been removed from most vaccines before 2001; no association had been found in subsequent studies. According to CDC flu vaccines contain thimerosal, and there may be trace amounts in some pediatric vaccines.


An autistic brain undergoes a period of precocious growth during early postnatal life (1st year of life through early childhood) followed by a deceleration in age-related growth, based on head circumference and MRI studies. (2)

  • Abnormal brain enlargement in children with autism is disproportionately accounted for by increased white matter.
  • Precocious enlargement in amygdala begins early and persist into late childhood; it does not undergo normal growth spurt in latency and adolescence. Adult autistic patients may have normal or decreased size amygdala.
  • Disproportionate grey matter increase is seen in the number of prefrontal neurons and Purkinji cells in the cerebellum.

More recent studies have found that brain overgrowth, at least as measured by head circumference, is subtle (~5mm) in idiopathic autism, and is limited to boys (JACAAP 2014, 53:10)


Informal screening

The following questions are useful as a quick screening for risk of autism in 18-24 mo toddlers:

  • social relatedness: does your child imitate you? does your child take an interest in other children?
  • pretend play: does your child ever pretend, for example, to talk on the phone or take care of dolls, or pretend other things?
  • joint attention: does your child ever use his/her index finger to point, to indicate interest in something? does your child ever bring objects over to you [parent] to show you something? if you point at a toy across the room, does your child look at it?
  • social referencing: does your child look at your face to check your reaction when faced with something unfamiliar?

Clinician can also check for eye contact, pretend play, and gaze monitoring and joint attention during the visit.

Checklist for Autism in Toddlers

  • original CHAT screened 18-mo old and included a yes/no parent questionnaire, and an observational component, filled out by a doctor; it showed high specificity but low sensitivity (~30%) in detecting autism.
  • Modified CHAT or M-CHAT expanded the parent questionnaire to 20 items and eliminated physicians' observational component: it was studied in children 18 - 30 months and had good sensitivity (85%) and specificity (99%).


  • Screening Tool for Autism in Two-Year-Olds, has higher sensitivity (93%), but lower specificity (80%) has to be administered by a trained observer.

Early intervention is crucial in autism; children who screen positive, should be referred for developmental services/intervention, even before definitive diagnosis can be made.


Children suspected of having autism should undergo a hearing test and have serum lead level checked.

DSM-IV-TR had 4 distinct disorders under the PDD umbrella:

  • autistic disorder (autism),
  • Asperger’s disorder,
  • childhood disintegrative disorder,
  • pervasive developmental disorder NOS.

Diagnosic crietria for autism spectrum disorders were changed in DSM-5. Autism spectrum disorder is a new DSM-5 collective name for the four previously separate disorders, since they are now recognized as a single condition with different levels of symptom severity.

Two of the 3 of the domains of impairment (social impairment and communication impairment) were collapsed into one.

  • This was based on the finding that the symptoms of autism which DSM-IV-TR assumes to reflect two distinct social and communication dimensions are actually manifestations of a single social communication factor.
  • The domain of restricted/repetitive behaviors was found to be distinct from the social/communication dimenstion (Mandy, William PL. JACAAP 2012(1).)
  • The criteria for stereotyped/repetetive language was moved from the communication domain to the repetetive behaviors domain.


Intensive Early intervention

Early Start Denver Model (ESDM), a comprehensive developmental behavioral intervention, delivered by trained therapists and parents for 2 years, starting before 30 mo of age. When compared with children who received community-intervention in a RCT (4), children who received ESDM showed significant improvements in

  • IQ,
  • adaptive behavior, and
  • autism diagnosis.


  • Risperdone and aripiprazole have FDA indicaitons for irritability in children with ASD
    • Risperidone or aripiprazole combined with parent training resulted in greater reduction of serious maladaptive behaviors than medication alone, in two randomized trials (Aman MG, JACAAP 2009(12) and Scahill L, JACAAP 2012(2).)
  • Cochrane review of aripiprazole (Abilify) for ASD found it to be effective in decreassing irritability, hyperactivity, and stereotypies. Notable side effects were weight gain, sedation, drooling, and EPS. (2012)
  • Donepezil may have a role in treating ADHD-like symptoms in children with PDD (case series, n=8) (Doyle RL, J Attention Disorders, 2006)
  • Omega-3 fatty acids have been shown to reduce aggression and self injury in a small placebo-controlled trial.

Other treatments

Cochrane Reviews were conducted on the following treatments; there was no evidence to support their use at this time (either no efficasy or too little data):

  • secretin injections
  • accupuncture
  • Tricyclic antidepressants


(1) Croen LA, Grether JK, Yoshida CK, Odouli R, Hendrick V. Antidepressant use during pregnancy and childhood autism spectrum disorders. Arch Gen Psychiatry. 2011;68(11):1104-1112.
(2) Amaral et. al. Neuroanatomy of Autism. Trends in Neurosciences 2008 31(3):137-145.
(3) Hultman et. al. Advancing paternal age and risk of autism: new evidence from a population-based study and a meta-analysis of epidemiological studies. Molecular Psychiatry (2011) 16, 1203-1212.
(4)Dawson G, Rogers S et. al. Randomized, controlled trial of an intervention for toddlers with autism: the Early Start Denver Model. Pediatrics. 2010 Jan;125(1):e17-23
(5) Atladóttir HÓ, et. al. Autism after infection, febrile episodes, and antibiotic use during pregnancy: an exploratory study. Pediatrics. 2012 Dec;130(6):e1447-54

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