Calling every mass shooting a mental health problem is "inaccurate and it's stigmatizing," said Arthur Evans, chief executive officer of the American Psychological Association.
About 1 in 5 adults in the United States, or 46.6 million, experience mental illness in a given year, according to the National Alliance on Mental Illness.
It's estimated that less than 5% of shootings are committed by people with a diagnosable mental illness, Post said.
"Mental health definitely has a role in gun shootings and that's mostly people who are depressed and kill themselves however, not mass shootings," she said.
Stigma can be a harmful result of routinely blaming mass shootings on mental illness, Rosie Phillips Davis, president of the American Psychological Association, said in a written statement after the shootings.