Kids with autism are more likely to be bullied by both their siblings and their peers, meaning that when they return from school, they have no respite from victimisation, warn researchers.
The study, published in the journal Autism and Developmental Disorders, also found that children with autism are more likely to be both the victims and perpetrators of sibling bullying compared to those without autism.
"Children with autism experience difficulties with social interaction and communication, which may have implications for their relationships with siblings," said study lead author Umar Toseeb from the University of York.
"From an evolutionary perspective, siblings may be considered competitors for parental resources such as affection, attention and material goods - children with autism might get priority access to these limited parental resources leading to conflict and bullying between siblings," he said.
The researchers used data of over 8,000 children, more than 231 of which had autism, to investigate sibling bullying.
For the findings, the children were asked questions about how often they were picked on or hurt on purpose by their siblings and peers and how often they were the perpetrators of such acts.
The study revealed that, at the age of 11 years, two thirds of children with autism reported being involved in some form of sibling bullying.
While there was a decrease in bullying for children in both groups by the time they reached the age of 14 years, children with autism were still more likely to be involved in two-way sibling bullying, as a victim and a perpetrator.
According to the researchers, children involved in sibling bullying, irrespective of whether they had autism or not, were more likely to experience emotional and behavioural difficulties both in the long- and short-term.