Autistic children could benefit from the presence of a dog, it has been suggested.
Researchers from the University of Montreal revealed that specifically trained service dogs had a positive impact on the anxiety levels of children with Autism Syndrome Disorders.
Furthermore, the dogs were found to improve the socialisation skills of the children.
Sonia Lupien, senior researcher and a professor at the university, commented: "Out findings showed that the dogs had a clear impact on the children's stress hormone levels.
"I have not seen such a dramatic effect before."
Published in Psychoneuroendocrinology, the report suggested that the animals could provide a "relatively simple" method of taking some of the stress out of the lives of the children and their family.
The researchers determined the children's stress levels by looking at the amount of cortisol in their saliva.
Cortisol is a hormone produced in reaction to stress and tends to peak around a half an hour after waking up and decline during the course of the day.