Researchers say that the effect of nicotine on brain activity may exacerbate Post-Traumatic Stress Disorder (PTSD) among smokers, and that alcohol, tobacco and other drug use by PTSD patients suggests the need for simultaneous treatment of co-occurring addictive and mental-health disorders, the Associated Press reported April 14.

Few treatment programs address PTSD and addiction at the same time. "It's kind of a clinical myth that you can only do one at a time or should only do one at a time," said Jean Beckham, a PTSD specialist and psychologist at the Veterans Affairs Medical Center in Durham, N.C.

Although some PTSD patients say a cigarette helps their mood when they're having symptoms, Beckham said nicotine's known ability to sharpen attention may reinforce bad memories. "If you think about your traumatic event and you smoke your cigarette, you can think about it even better," said Beckham.

A new report from the National Institute on Drug Abuse found that addiction causes changes in some of the same brain areas disrupted by mood and anxiety disorders like PTSD. Up to 60 percent of people in addiction treatment are estimated to have PTSD, and those with PTSD are three times more likely than other patients to drop out of treatment.

PTSD has received renewed attention as U.S. veterans return from combat in Iraq and Afghanistan. A study last year by the RAND research organization estimated nearly 20 percent of returning soldiers have symptoms of PTSD or major depression.