A new study published in JAMA Psychiatry finds a link between post-traumatic stress disorder and food addiction among women, potentially explaining why past research has associated the disorder with an increased risk of obesity.
Post-traumatic stress disorder (PTSD) is an anxiety disorder caused by extremely stressful or frightening events involving actual or perceived threats to one’s life or physical integrity. An estimated 7.7 million adults in the U.S. are currently diagnosed with the disorder, which can occur immediately after the traumatic event but can also take weeks, months or even years to develop. Symptoms of PTSD can include nightmares and flashbacks, insomnia, nervousness, lack of concentration, and feelings of isolation, irritability, numbness, and/or guilt.
Past research suggests a link between PTSD and eating disorders such as anorexia nervosa and bulimia nervosa. According to one estimate, up to 37 percent of women with bulimia also have PTSD. The common link, scientists say, is trauma, which is associated with both PTSD and maladaptive eating behaviors. For women with a history of trauma, the symptoms of eating disorders likely serve as a coping mechanism to manage or regulate uncomfortable and distressing emotions.
An increasing number of studies have also linked PTSD to a higher risk of obesity and its related diseases, explain the team behind the new analysis, led by senior author Susan M. Mason, PhD, of the University of Minnesota. Last year, for example, researchers from the Harvard School of Public Health in Boston, MA, found that women who suffer from symptoms of post-traumatic stress disorder have an increased risk of becoming overweight or obese.
Dr. Mason and colleagues note the reasons behind such associations are poorly understood; in the new study, the team wanted to look at whether food addiction may play a part. “Food addiction is not currently established as a psychiatric diagnosis,” say the researchers. “However, the concept may nonetheless be helpful for identifying the reliance on food to cope with psychological distress, one plausible pathway from PTSD to obesity.”
Women with severe PTSD ‘had twice the prevalence of food addiction’
The team conducted a cross-sectional analysis of 49,408 women who were a part of the Nurses’ Health Study II and were between the ages of 25 and 42 years-old at the time of recruitment to the study in 1989. In 2008, participants completed a questionnaire disclosing their experiences of any traumatic events and symptoms of PTSD. In 2009, participants were assessed for symptoms of food addiction.
Participants were classified as having food addiction if they had three or more clinically significant symptoms, as defined by the Yale Food Addiction Scale. Symptoms included eating when no longer hungry four or more times each week, feeling the need to eat higher amounts of food to reduce stress at any point, and worrying about reducing food intake four or more times a week.
Of the 81 percent of women who had experienced at least one traumatic event, 34 percent reported no symptoms of PTSD, 39 percent reported 1-3 of the 7 symptoms listed on the questionnaire, 17 percent reported 4-5 symptoms, and 10 percent reported 6-7 symptoms. On average, women reported experiencing their first PTSD symptom around the age of 30.
The team found that the prevalence of food addiction increased as the number of PTSD symptoms increased. Only 6 percent of women with no PTSD symptoms had food addiction, compared with nearly 18 percent among women who had 6-7 symptoms of PTSD. Furthermore, the earlier the age at which PTSD symptoms occurred, the stronger the association with food addiction.
“To our knowledge, this study provides the first evidence of an association between PTSD symptoms and food addiction, two disorders of emerging concern for obesity risk,” the team writes. “Our findings are consistent with the hypothesis that observed links between PTSD and obesity might be partly explained by a tendency to use food to self-medicate traumatic stress symptoms.”
There are several limitations to the study that could influence the results. The team points out that they assessed symptoms of PTSD through a questionnaire rather than a diagnostic interview, which they say could have influenced the accuracy of PTSD diagnosis. Future research should seek to replicate these findings in a longitudinal analysis using established diagnostic methods, the researchers add.
The ‘controversial’ science of food addiction
The researchers also note that the idea of food addiction is “controversial,” and whether their findings apply clinically depends on whether mental health professionals deem food addiction a “legitimate psychiatric diagnosis.” “However,” the team adds, “we believe that the value of the food addiction construct goes beyond its identification of psychiatric illness by capturing a potentially important maladaptive coping behavior that may provide insight into mechanisms linking trauma and PTSD to obesity.”
Indeed, with obesity rates climbing in unison with the availability of refined foods, there is growing concern that food addiction may play a large role in the obesity epidemic. Research suggests that foods rich in fat and sugar may hijack the brain in ways that resemble addictions to cocaine, nicotine and other drugs. When eaten, these foods can supercharge the brain’s reward system, which in turn can overpower the brain’s ability to tell an individual to stop eating.
For instance, a study published in June found that women who struggle with binge eating were more impulsive than average in a food-related psychology test, suggesting that they are more instinctively stimulated by images of food. Further, some women reported food cravings even if they had eaten recently, a symptom of possible food addiction.
The new findings add to this growing body of evidence suggesting that overeating is a much more complex problem that we initially believed. Until the early 1990s, society viewed obesity solely as a behavioral problem: overweight individuals lacked willpower and self-control. Since then, the view has changed dramatically — in the scientific community at least (unfortunately, obesity-related stigma is still a major problem in our society, despite the fact that nearly one-third of Americans are obese and more than one-third are overweight).
While not all overweight or obese individuals suffer from food addiction, it seems certain that some are. The more quickly the medical community embraces the science of food addiction, the sooner we can start to help sufferers and possibly even prevent it in the future.