A new study, published recently in the Journal of Clinical Psychopharmacology, has found that most American mass shooters had an untreated mental illness, according to U.S. News.

The study’s lead researcher Dr. Ira Glick said, “Without losing sight of the larger perspective that most who are violent are not mentally ill, and most of the mentally ill are not violent.”

“Our message is that mental health providers, lawyers, and the public should be made aware that some unmedicated patients do pose an increased risk of violence,” wrote Dr. Glick, who is a professor of Psychiatry and Behavioral Sciences at the Stanford University Medical Center, Emeritus.

Dr. Glick and his colleagues studied 35 mass shooting cases that occurred in the United States from 1982 to 2019, including shooters who survived and were brought to trial.

Of all those mass shooters included in the study, 28 were diagnosed with mental health disorders, with 18 having schizophrenia and 10 having other issues such as bipolar disorder, delusional disorder, personality disorders, and substance-related disorders.

Of the 28 mass shooters with mental health issues, nobody was medicated or received any treatment before committing their crimes, according to the researchers.

Dr. Glick and the team also reviewed 20 mass shooters who died at the crime scene. They found that eight had schizophrenia, seven had other mental health diagnoses, and five had unknown diagnoses. Nobody received appropriate medications.

The researchers noted there is no research on the nature and incidence of mental health issues in people who commit these crimes despite a high frequency of mass shooting events in the United States.

The authors said in a news release, “The psychiatric disorders seen in perpetrators of mass shootings are serious brain illnesses – as much in need of proper diagnosis and treatment as heart disease or any other medical condition.”

“We need to reduce the stigma associated with these diseases to enable patients to receive appropriate and adequate psychiatric medication and other treatments by actually talking to patients and their significant others, we have the opportunity to save lives,” they added. The article was published in U.S. News.