Washington D.C.: According to a new study, veterans who have drug or alcohol problems are more than twice as likely to die by suicide as their comrades.

The research published in the journal Addiction finds highest suicide risks are among those, who misuse prescription sedative medicines, such as tranquilizers. Women veterans who misuse opioid drugs also have an especially high risk of suicide. The study finds highest suicide risks are among those, who misuse prescription sedative medicines, such as tranquilizers. Women veterans who misuse opioid drugs also have an especially high risk of suicide.

The findings point to a need to focus more veteran suicide-prevention efforts on those, who have substance use disorders, especially if they also have depression, schizophrenia, bipolar disorder, post-traumatic stress disorder or anxiety. These findings come from one of the largest-ever examinations of substance use disorders and suicide, involving more than 4.4 million veterans.

"We hope these findings will help clinicians and health systems care for people with substance use disorders, with mental health conditions, and with both -- and focus suicide prevention efforts accordingly. Substance use disorders may be important markers for suicide risk," says Kipling Bohnert, Ph.D., lead author of the study and researcher with the VA Center for Clinical Management Research who is also an assistant professor of psychiatry at the U-M Medical School.

Using statistical techniques, the team calculated suicide rates per 100,000 veterans, and then calculated those rates for veterans with substance use issues overall, and for specific substance use disorders. In all, the suicide rate was 75.6 per 100,000 for veterans with any substance use disorder, compared with 34.7 for veterans overall.

A previous study led by Mark Ilgen, Ph.D., co-author on the new study, found similarly higher rates in veterans who were tracked from 1999 to 2006. But the new study lets the researchers drill down to the specific substance that veterans had problems with, including alcohol, opioids, marijuana, and cocaine.

The study found the suicide risk was highest for veterans of both genders who misused sedatives -- 171.4 per 100,000 -- and markedly higher for women who misused opioids, at 98.6 per 100,000.

The researchers then took into account veterans' age and the overall severity of their medical conditions, and calculated the risk of suicide by type of substance use disorder. Men who misused amphetamines also had a suicide rate of 95 per 100,000. Among women, only alcohol and opioid disorders remained associated with higher suicide risk, independent of mental and physical health.

Bohnert adds, "Assessment and treatment of co-existing psychiatric conditions, in addition to substance use, may be important in lowering the risk of suicide among individuals who have substance use disorders."

But both genders with substance use disorders had a higher rate of suicide even after differences in physical and mental health were factored in.