An Ontario-based study says that roughly one in six people with autism had at least one interaction with police over an 18-month period.
And while criminal charges were laid in only two incidents involving study participants, police intervention was reported to increase distress in about one third of the cases.
The study, a collaboration between Toronto's Centre for Addiction and Mental Health and York University, surveyed the caregivers of 284 Ontario teens and adults.
The caregivers reported police interactions for 46 people, or about 16 per cent.
The study says that in nearly one in five cases, the person ended up in physical restraints. In nearly one in three, the person was escorted to an emergency department.
Researchers note the study may be limited in that its sample may not be representative of all individuals with autism and their families, but say it suggests a need for police training on the range of behaviours people with autism can exhibit.
Meanwhile, advocacy groups say there are practical steps that people with autism and their families can take to reduce the likelihood of a negative experience with police, including placing stickers in car or home windows to indicate the presence of a person with autism, and engaging with neighbours, who are often the ones to call police.
The study found that those with less severe autism symptoms were just as likely to interact with police as those with more severe symptoms, but the most common reason reported for an interaction with police was aggression.
Those who were older and living outside of their family's home with less structure in their lives were more likely to encounter police, the data show.
Relatives of those who interacted with police were also more likely to show signs of caregiver fatigue, the study says.
The executive director for Autism Ontario expressed concerns about the number of negative experiences reported by participants.
"Any interaction with police and vulnerable citizens should go well," Margaret Spoelstra said in a statement. "It's worrisome."