Irritable bowel syndrome (IBS) affects 10 to 20 percent of Americans, the majority of them women. Symptoms include constipation, severe diarrhea, or a combination of both, along with nausea and stomach pain. Despite its impact on the quality of life of millions of people worldwide, IBS remains poorly understood and both difficult and frustrating to treat.
Yuri A. Saito Loftus, M.D., a clinical researcher at Mayo Clinic in Minnesota, says that one approach is to consider psychological factors in patients with IBS, noting that stress can worsen symptoms and that comorbidities such as anxiety and depression are common.
"Childhood physical and sexual trauma have both been implicated in adult IBS, but other types of trauma have been less well studied, especially with regard to families," she says. "I'm very interested in genetic and environmental triggers in the development of IBS, and I wanted to look at different forms of trauma in greater detail."
To do so, Dr. Saito Loftus and colleagues re-contacted participants in an earlier large-family, case-controlled study. In all, 4,520 people were sent the Early Trauma Inventory Self Report, which collects information about emotional, sexual and physical abuse as well as general traumatic experiences ranging from parental loss to natural disasters.
Of those contacted, 58 percent agreed to participate — a total of 430 cases, 447 controls, 827 case-relatives and 921 control-relatives.
Based on the survey reports, people with IBS experienced more trauma over a lifetime than controls did. Traumatic events, which were equally common before and after age 18, included natural disasters, serious accidents, divorce, the death of a sibling, exposure to violence, and feeling belittled or misunderstood.
Patients with IBS were not more likely to report experiencing the death of a friend, observing a murder, being burned or having certain sexual encounters.
"The long and the short of it is that the presence of early-life trauma — and not necessarily abusive trauma — is predictive of adult IBS," Dr. Saito Loftus says. "Further, psychological and physical stressors over a lifetime may contribute to the disease."
She says that evidence about family members is less compelling. "Trauma scores were generally similar between case-relatives and control-relatives; there was a slight trend but not enough to be statistically significant," she explains. "But family members with IBS did have higher trauma scores than those who did not have the condition."
One of the limitations of the study, Dr. Saito Loftus notes, is that researchers were unable to learn the full measure of how people with IBS are affected by trauma. For instance, the impact of a distressing event is likely influenced by a person's age at the time, how other people cope and how much support the traumatized person receives. She adds that measures of emotional abuse, such as feeling unloved or misunderstood, are highly subjective and impossible to quantify.
Trauma doesn't explain all cases of IBS, Dr. Saito Loftus says, but it does explain psychological comorbidities such as depression. And, she adds, some people have a genetic susceptibility to gut dysfunction that may be exacerbated by early life experiences.
"I think trauma as a contributing factor is underrecognized and not addressed early enough or well enough," she says. "It's important to dispel the old myth that IBS is psychosomatic because that is simply not true. And if patients with IBS also present with anxiety or depression, we should inquire whether they have seen a psychologist. We should be addressing these issues, especially now that we have clear evidence that what people are experiencing in their early years can affect their health in adulthood."
In the past, Dr. Saito Loftus says, the lack of a clear cause for IBS paralyzed physicians. But she stresses that psychological counseling is something that should now be considered when determining treatment.