A study by researchers from the University of California shows early symptoms of autism, such as, refusal to make eye contact, smiling and communicative babbling are not present in six month old babies. Rather, emerging gradually they only become apparent towards the latter half of their first year of life.

For the study, behaviour of siblings of children diagnosed with autism was compared by researchers to that of normally developing babies.

The five year old study conducted at the M. I. N. D Institute in Sacramento involved a painstaking count of each smile, babble and eye contact by researchers during the examination of the children till they were three years of age.

They found symptoms of autism emerged after six months, with a significant difference in the development of the two groups by 12 months.

Children developing normally showed an increase in intentional social and communicative behaviour, which dramatically decreased amongst infants later diagnosed with autism.

Professor Sally Ozonoff, the study’s lead author in a news release said, behavioural signs of autism appear in the latter half of the first year of life for most autistic children. Most babies are born relatively normal in terms of their social abilities, however, via a gradual process of decline in social responsiveness, autism symptoms start to emerge between six and 12 months of age.

Autism, according to the National Autism Society is a lifelong pervasive developmental disorder affecting a person’s social skills and communication, as well as, in repetitive and restricted behaviours, with onset occurring prior to age 3. Autistic people have difficulties with everyday social interaction. Abnormal brain development, probably beginning pre-natally is known to be fundamental to the behaviours that characterize autism.

Children with a sibling who has been diagnosed with autism are at greatest risk of developing the disorder.

For the current study, 25 high-risk children meeting the criteria for autism at three years of age were matched with 25 low risk peers developing normally.

The study notable because of the accuracy and precision of its prospective methodology, has been published online and will also appear in the Journal of the American Academy of Child & Adolescent Psychiatry March issue.