The case against a U.S. soldier who is accused of killing 17 civilians in Afghanistan has focused attention on the mental health problems some soldiers experience after years of combat. War veterans with a condition known as post-traumatic stress disorder, or PTSD, were twice as likely to be on high-risk drugs as those with no mental health issues. The U.S. war in Afghanistan is the longest military conflict in American history. Many of the troops who have fought there also saw combat in Iraq. Doctors say at least one third returned with mental health problems. Dr. Michael Yochelson was part of a military medical team that assessed returning soldiers for post-traumatic stress disorder and traumatic brain injury. "I think it's going to be really critical that those personnel are identified and get into therapies quickly," Yochelson said. But what kind of therapies are most effective? Researchers studied a group of more than 140,000 U.S. military veterans who had served in Iraq and Afghanistan between 2005 and 2010, and who had been prescribed an opioid -- a narcotic -- within a year of getting a pain diagnosis at a veterans' hospital. Dr. Karen Seal is a co-author of the study. "Veterans who had a mental health diagnosis, but particularly PTSD (post-traumatic stress disorder) were far more likely than their counterparts without mental health problems to receive opiate pain medication," Seal said. Veterans with PTSD were 2 1/2 times more likely to be on these narcotics. The researchers also were also concerned about the quantity of drugs prescribed. "These patients tend to receive higher dose opiates than their counterparts and would request early refills of their opiates, which indicates that they are using them more quickly than they should be," Seal said. Many of the veterans on these drugs -- whether they were mentally ill or not -- had higher rates of accidents, alcoholism, violent injuries, suicides and overdoses. Seal says the findings demonstrate that alternative methods of treatment, such as physical therapy, talk therapy or acupuncture, should be offered more widely. "The study really woke us up to the reality of the serious adverse consequences that can occur with the use of opiates in returning Iraq and Afghanistan veterans who have pain and mental health problems," Seal said. Yochelson says treating post-traumatic stress disorder will take more than a quick fix. "Frankly, if they've been on multiple deployments and perhaps been there for 12 or 18 months or longer, or even over a period of several years, several deployments and never had it addressed until now, I think that treatment period may be going on for several years and maybe indefinitely," Yochelson said. The study was published in the Journal of the American Medical Association.