Women who have the largest number of post-traumatic stress disorder symptoms are almost three times more likely to develop an addiction to food, a new study suggests.
The findings don't prove a direct link between PTSD and women overeating or becoming addicted to food. And it's also possible that certain women are prone to food addiction and experiencing trauma, PTSD, or both.
Still, the research seems to add to existing evidence connecting PTSD to overeating and obesity, although the overall risk is fairly low, the researchers from the University of Minnesota said.
The findings can be helpful, said the study's lead author, Susan Mason, an assistant professor with the university's division of epidemiology and community health. "If clinicians providing mental health care are aware that PTSD is sometimes accompanied by problematic eating behaviors, then they may be able to offer better and more tailored care to their patients," she said.
PTSD is an anxiety disorder that develops in some people after they experience a horrific event, like a natural disaster, violence or warfare. Those with PTSD may become endlessly vigilant, have a difficult-to- impossible time relaxing, and can develop flashbacks, nightmares and severe anxiety.
Previous research has linked PTSD to higher rates of obesity and being underweight, Mason said, along with addiction problems. It's difficult for researchers to figure out exactly what's going on, however, because they can't use the gold standard of research, a clinical trial, to examine a possible connection. It would be unethical -- and probably impossible -- to randomly assign some people to develop PTSD and then compare them to healthy people.
In the new study, researchers tried to get a handle on possible connections between PTSD and food addiction.
Food addiction is defined as a kind of psychological dependence on food, with symptoms like other kinds of addictions. For instance, physical withdrawal if those with the disorder stop eating certain foods, using food to make them feel better and eating when they don't need to.
Mason said she wasn't aware of research pinpointing how many people suffer from food addiction.
The researchers examined the results of Nurses' Health Study II surveys of more than 49,400 female nurses in the United States in 2008 and 2009. The women joined the study in 1989 when they were 25 to 42 years old.
According to Mason, the researchers found that 6 percent of the one-third of women who had no signs of PTSD showed signs of food addiction. Of the 10 percent of women who had the most symptoms -- 6 to 7 on a 7-symptom PTSD screening questionnaire -- nearly 18 percent had a food addiction.
The researchers noted two things: Nurses reported their most common trauma experience was treating individuals with traumatic injuries, and early onset of symptoms predicted a higher prevalence of food addiction.
Why do these numbers matter? "It is a big deal if a substantial proportion of women are feeling highly distressed or feel that their functioning is being undermined by their relationship with food," Mason said.
Still, she said it's not clear how all this is connected to obesity. The nurses in the study who seem to be addicted to food "are substantially heavier than women who do not meet those criteria, but we don't yet know whether the food addiction causes obesity, or the other way around, or if the two things are both caused by some underlying factor we don't know about."
Dr. Timothy Brewerton, executive medical director with The Hearth Center for Eating Disorders in Columbia, S.C., praised the research. "This study represents a major advance in validating the concept of food addiction, and in linking food addiction with trauma and PTSD," he said.
He noted that the study adds support for the idea that food addiction is real -- "there are a lot of naysayers in the eating disorders community in regard to the existence of food addiction"-- and suggests that trauma and PTSD could be a cause. "The greater the number of PTSD symptoms, the greater the probability of food addiction," he said.
As for future research, Mason said researchers want to look at larger groups of people to see if the connection holds up.
The study appears in the Sept. 17 issue of JAMA Psychiatry.