A new study finds people with mental illness who also have a substance use disorder are nine times more likely than the general population to be murdered. Overall, people with mental illness were almost five times as likely to be a murder victim, compared with those with no psychiatric diagnosis.

The researchers studied Swedish government data covering psychiatric diagnoses and causes of death among the nation’s 7.2 million adults, from 2001 to 2008. During that time there were 615 murders; 141 of the victims had a mental disorder, The New York Times reports.

People with personality disorders were three times more likely to be murdered compared with the general population. People with depression were 2.6 times more likely to be murdered, while having an anxiety disorders increased the risk 2.2 times, and schizophrenia, 1.8 times.

The Stanford University researchers noted that while the issue of homicide by people with mental disorders has received much attention, their risk of being a victim of homicide has rarely been examined.

The study appears in the British Medical Journal.