Time Trends in Treated Incidence, Socio-demographic Risk Factors, and Co-occurring Psychiatric Disorders in Diagnosed Autism Spectrum Disorder With or Without Intellectual Disability: A Finnish Nationwide Register Study

The increase in diagnosed ASD, particularly without ID, recorded by specialized services in Finland between 1998 and 2018 may reflect a real increase in incidence, or changes in diagnostic criteria and practices, improved mental health services, greater public and professional awareness or treatment seeking behavior.