WEDNESDAY, Dec. 28 (HealthDay News) -- Instant communication may be all the rage, but old-fashioned letter-writing may have a more beneficial lasting effect on recipients.

In a study involving soldiers serving in war zones, most in Iraq, researchers found that letters from home -- just a few words from the heart, scribbled onto paper or typed into an email -- served as an inoculation against one of war's most insidious and long-lasting wounds. Recipients were less likely to exhibit symptoms of post-traumatic stress disorder.

"Those positive, permanent forms of communication may have mental health benefits," said Benjamin Loew, a graduate research assistant in the psychology department at the University of Denver who co-authored the study, published in the Journal of Traumatic Stress.

More "instant" forms of communication, such as telephone calls or video chats, did not have the same positive effect on soldiers' mental well-being as the receipt of written communication or even care packages, the study found.

One theory why this is the case, according to the researchers, is that people tend to think through what they write in a letter and are less likely to be argumentative and more free to share affection and other positive feelings.

"These delayed forms of communication are going to be protected from conflict-type discussion," Loew said.

Letters also serve as mementos that soldiers can carry with them as a reminder of home.

"A soldier could repeatedly pull out a letter or an e-mail and feel support," Loew said. "A phone call can be recalled but can't be re-experienced. A letter can be read over and over again."

That makes perfect sense to Marion Frank, a Philadelphia psychologist and past president of the Philadelphia chapter of the Gold Star Wives of America, an organization for military widows and widowers.

"There is more thought that goes into writing, versus a call or a text message," Frank said. She also agrees that a letter's value as a memento likely adds to its value in helping soldiers cope with their circumstances.

"When we have something from a loved one, it has meaning and it gives us comfort," she said.

Such physical forms of communication can help even if a person isn't in the high-stress environment of combat, Frank said. Letters, cards and emails can help bolster the spirits and possibly reduce the stress of family and friends who are away at college or on an extended business trip, for instance.

"It certainly helps if you're leaving a loved one," Frank said. "When people send a memento or a card, it helps the person feel connected to home. It's the whole idea behind the greeting card industry."

However, Frank said such letters would probably not have the same effect as those received by people in the sort of high-risk, high-stress, life-threatening situations that can produce post-traumatic stress.

"That's when you're in danger in terms of your life," she said. "In civilian life, letters and cards won't prevent stress from happening, but they can be helpful in reducing stress for people who have left a loved one."

But for those in the military, the aftereffects of trauma can be powerful.

"What people are doing in the service often exposes them to traumatic experiences," Frank said. "Even if they have this kind of concrete support, they could still suffer PTSD."

Post-traumatic stress disorder is a form of anxiety brought on by exposure to a horrific, life-changing or traumatizing event, according to the U.S. Department of Veterans Affairs. Symptoms can include reliving the event in your mind, avoiding things that remind you of the event, feeling numb to the world around you or becoming jittery, keyed-up and on a hair trigger.

The U.S. Department of Veterans Affairs has estimated that PTSD afflicts nearly 31 percent of Vietnam veterans, 10 percent of Gulf War (Desert Storm) veterans, 11 percent of veterans of Afghanistan fighting and 20 percent of Iraq war veterans.

For the study, the research team surveyed 193 married Army soldiers at Fort Campbell, Ky., who had returned in the past year from an overseas tour that included combat. They evaluated each soldier for PTSD symptoms, their exposure to combat and their marital satisfaction. They also quizzed each soldier on the frequency and types of communication they had received from home while they were deployed.

They found that happily married soldiers who received frequent communication that the team described as delayed -- letters, emails, care packages -- had fewer PTSD symptoms than those who'd received more instant communications, such as phone calls, video chats and instant messages.

But they also detected one scenario in which letters from home proved detrimental.

Soldiers in unhappy marriages who communicated often by delayed means tended to have more PTSD symptoms, the study found.

"We don't know if the communications are more negative, or if it reflects a soldier doing a lot of writing home and not getting anything in return," Loew said.

More information

The U.S. National Institute of Mental Health has more on PTSD.