Teenagers with difficulties in social communication, including autism have higher rates of depressive symptoms, especially if they are being bullied.
Researchers at the University of Bristol, using questionnaire, clinic and genetic information on 6091 young people from the Children of the 90s longitudinal study, found that children with autism and those with autistic traits had more symptoms of depression when they were 10 years old than their peers and that this continued at least up to the age of 18.
Children with difficulties in social communication were also more likely to have a diagnosis of depression at 18 and the findings suggest an increased risk for those who suffered from bullying. The researchers did not find any link between having higher genetic tendencies towards autism and depressive symptoms.
Dr Dheeraj Rai, Consultant Senior Lecturer in Psychiatry at the Centre for Academic Mental Health said: "We still know very little about why mental health problems are common in autism and what could be done to address them.
"Thanks to the wealth of data collected within the Children of the 90s study, we tracked the development of depressive symptoms in children with autism and autistic features up to the age of 18 years.
"We found that these children have more depressive symptoms than their peers at age 10 and these continue through adolescence to age 18, especially in children who reported being bullied.
"More research needs to be done to understand other pathways contributing to the risk of depression in autism across the life course, but these findings suggest that focusing on the role of traumatic experiences such as bullying and interventions targeting these, could be important and may have the potential to make a real difference to the wellbeing of autistic people."
Alan Emond, Professor of Child Health at the Centre for Child and Adolescent Health at the University of Bristol added: "Bullying can be detrimental to anyone's mental health, but young people with social communication difficulties and other autistic traits seem to be particularly vulnerable. To protect autistic children and young people a whole school approach is needed to prevent bullying, coupled with targeted support for vulnerable individuals."
Dr James Cusack, Director of Science at Autistica, the charity for autism research, said: "Autistic people and families have told us that mental health is their top priority for research. This is not surprising as we know autistic people experience high rates of chronic mental health problems which lead to tragically high rates of suicide. Yet, our knowledge of autism and depression has remained poor.
"This excellent study tells us that symptoms of depression are elevated in autistic adolescents. The authors found that it was bullying rather than genetic differences which drove an increase in depressive symptoms in autistic people.
"We now urgently need to carefully understand bullying and other traumatic experiences in autistic people as we're now finding they can have a devastating impact.
"As the UK's autism research charity, we will be working hard to ensure that further research on priority areas like this is supported. If we can improve the mental health of autistic people we can go a long way to ensuring they can live the long, healthy, happy life they deserve."