Reaching for a cigarette to cope with a flashback is all too common among sufferers of post-traumatic stress disorder.

The nicotine hit may feel good but scientists say its brain action probably makes their PTSD worse in the long run.

Here's the rub: At least half of PTSD sufferers smoke, and others wind up dependent on alcohol, anti-anxiety pills, sometimes even illegal drugs. Yet too few clinics treat both PTSD and addictions at the same time, despite evidence they should.

Now studies are recruiting PTSD patients - from New England drug-treatment centers to veterans clinics in North Carolina and Washington - to determine what combination care works.

"It's kind of a clinical myth that you can only do one at a time or should only do one at a time," says Duke University PTSD specialist Dr. Jean Beckham, a psychologist at the Durham, N.C., Veterans Affairs Medical Center. "Everybody's afraid to have their patients quit smoking because they're afraid they're going to get worse. There's not a lot of empirical data about that."

And her research on how to break the nicotine-and-PTSD cycle raises a provocative question for a tobacco-prone military: Are people at higher risk of developing PTSD if they smoke before they experience the violent event or episode?

Post-traumatic stress disorder - which can include flashbacks, debilitating anxiety, irritability and insomnia - is thought to affect nearly 8 million Americans at any given time. Anyone can develop it after a terrifying experience, from a mugging to a hurricane, a car crash to child abuse. But PTSD is getting renewed attention because so many veterans returning from combat in Iraq and Afghanistan seem vulnerable. A study last year by the RAND Corp. research organization estimated nearly 20 percent of them, or 300,000 people, have symptoms of PTSD or major depression.

What's less discussed is that patients often don't realize they might have PTSD and try to relieve symptoms by self-medicating with alcohol, tobacco and other substance use - worsening habits that existed before the trauma or starting anew.

Addiction itself is a mental health disorder that causes changes in some of the same brain areas disrupted by mood and anxiety disorders like PTSD, says a new report on the co-illnesses from the National Institute on Drug Abuse. That argues for simultaneous treatment. Indeed, up to 60 percent of people in addiction treatment are estimated to have PTSD - although they seldom acknowledge symptoms - and they're three times more likely than other patients to drop out.

A handful of studies suggest combo care helps. One example: VA researchers in Connecticut gave the alcoholism drugs naltrexone and disulfiram to PTSD patients, and watched not only their drinking ease but their PTSD symptoms improve, too.

Then there's nicotine. It temporarily enhances attention when it hits the brain - one reason that members of military tell the VA's Beckham they smoke. Although PTSD patients say a cigarette helps their mood when they're having symptoms, the extra attention may be reinforcing bad memories.

"If you think about your traumatic event and you smoke your cigarette, you can think about it even better," explains the VA's Beckham.

Yet the NIDA report found combination care rare, partly because of our specialty-driven health system.

Another big reason: "The majority of people with PTSD don't seek treatment," Dr. Mark McGovern of Dartmouth Medical School told a NIDA meeting this month that brought together military and civilian experts to jump-start research.

"People try to swallow it or take care of it on their own and it just kind of gets out of control," agrees Bryan Adams, 24, who is working with the Iraq and Afghanistan Veterans of America to raise PTSD awareness.

Adams, now a business major at Rutgers University, was awarded a Purple Heart after being shot when his Army patrol was ambushed in Iraq in 2004. Back home he handled restlessness and irritability with increasing alcohol use. Only when he got into college did a checkup lead to a PTSD diagnosis and therapy. He quit excessive drinking as the PTSD improved, despite no formal alcohol treatment.

The new studies may prompt more merging of care:

_In Durham, Beckham is giving PTSD-suffering smokers either a nicotine patch or a dummy patch to wear for three weeks before they quit smoking. The theory: Steady nicotine release will blunt a cigarette's usually reinforcing hit to the brain, possibly helping both withdrawal symptoms and the intensity of PTSD symptoms.

_In some New Hampshire and Vermont substance-abuse clinics, McGovern is randomly assigning patients to standard addiction-only care or cognitive behavioral therapy traditionally used for PTSD. A pilot study found the cognitive behavioral therapy improved both PTSD symptoms and substance use.

_In Seattle, researchers at the VA Puget Sound Health Care System have PTSD therapists conducting smoking cessation therapy in the same visit. In a pilot study, those patients were five times more likely to quit cigarettes than PTSD patients sent to separate smoking programs.