Relationship between Irritable Bowel Syndrome, Worry and Stress in Adolescent Girls

Irritable bowel syndrome (IBS) is a common functional gastrointestinal disorder and its characteristic symptoms are chronic abdominal pain or discomfort for over three months, abdominal distension and changes in bowel habit. Its prevalence was recorded to be around 10%-15% of adults in North America and to be 6.6% of adults in Korea (1, 2). IBS affects quality of life of individuals and many efforts to determine its causes have been made. The prevalence of children is similar with that of adults and the prevalence of females is known to be two times higher than that of males (3).

IBS often occurs just after gastroenteritis, after long-term gastroenteritis, in females or with associated with psychiatric stress. Stress can aggravate IBS symptoms in some cases (4). Psychiatric factors worsening IBS are anxiety, somatizing syndrome and depression (5, 6). Brown and Barlow reported that 55% of patients have symptoms meeting criteria for at least one additional anxiety or depressive disorder (7). On the contrary, IBS was observed frequently in patients with psychiatric diseases. Some studies found that 46% of panic disorder, 29% of major depression and 19% of schizophrenia were associated with IBS (8).

Stress is psychological pressure caused by an imbalance between ones' adaptive ability and the demand in persceptive environment by individual (9). Stress is more complex and has more social properties than worry. As normal developmental tasks, adolescents are exposed to severe stress caused by competition in relation to university entrance examination and academic performance. Especially Korean adolescents are under a lot stress and pressure because they have to culturally face a fierce competition in relation to the entrance examination. Most of psychiatric stress of adolescents is attributed by academic performance and career searching, which can be presented as anxiety, worry, depression and physical symptoms associated with them (10). These worries are known to be a critical symptom of generalized anxiety disorder or one of anxiety disorders (11).

On the other hand, worry is a generalized psychological phenomenon that can be seen among most people. Borkovec et al. (12) defined that worry is a chain of thoughts and images, negatively affect-laden and relatively uncontrollable. The worry process represents an attempt to engage in mental problem-solving on an issue whose outcome is uncertain but contains the possibility of one or more negative outcomes; Consequently, worry relates closely to the fear process. However, because worry in adolescents has been recognized as a relatively timid psychological phenomenon which is commonly experienced, it has not been dealt as a main topic of a certain study. But, many studies reported that when worry became severe not to be controlled, they could influence daily life and ultimately lead to an anxiety disorder (13, 14).

According to a study of Muris et al. (15) conducted with community children without anxiety disorder, about 6.7% showed an excessive worry exceeding the normal range and some of them had symptoms to be diagnosed as generalized anxiety disorder. According to another previous research, it reported that about 30% of normal group with no experience of psychological treatment showed a high level of worry (16). Like this, worry is a symptom to which we should pay attention but there has been nearly no study on correlation between IBS and worry. A recent study of Son et al. (17) reports that high school girls with IBS recorded higher anxiety score than those without it. Both in population and in clinical samples, women are almost twice as likely as men to meet diagnostic criteria for IBS (18, 19). Therefore, this study investigates prevalence of IBS and correlation among worry, stress and IBS with students in a girls' middle school and a girls' high school.

Keefer et al. (30) said that although patients diagnosed with IBS were found not to be highly anxious, they reported high levels of intolerance of uncertainty, which is a construct found to be highly related to worry. In addition, they also showed that worry and state anxiety were proved to be good predictors of GI symptom severity, accounting for almost 30% of the variance. They suggest that worry may be an important factor in the onset and/or maintenance of IBS. IBS patients and chronic worriers tent to devote higher levels of attentional resources toward monitoring threatening information and tend to perceive themselves as more vulnerable to disease (31-34). Unfortunately, the mechanism by which worry works in developing or maintaining IBS has yet to be elucidated.

IBS is one of functional gastrointestinal disorder occurring without an organic cause. As its symptoms are nonspecific and subjective, it is diagnosed by excluding other organic diseases. Studies to explain its mechanism have been researched and its pathologic mechanism is explained with brain-gut disorder although it is not clearly confirmed (4). Disorder of serotonin regulation cause changes of gastrointestinal movement and imbalance of absorption and secretion, and following abnormality of intestinal motility is considered to lead to abdominal pain and discomfort. In addition, not only changes of immune response and intestinal flora but also other various causes have been known to influence the complex gastrointestinal movement. So bowel hypersensitivity, brain-gut disorder and psychiatric and social factors have been recognized as possible mechanism (4, 6, 35).

Also in this study, students with IBS had a significantly higher stress score and anxiety score as well, which implies that mental stress or excessive worry could affect occurrence of IBS. In the case of the anxiety disorder, the hyperactivity of the central norepinephrine system or the abnormal activation of serotonin or GABA receptors acts upon it (7, 36, 37). Such neurotransmitters may cause motility disorder in the gastrointestinal system or abnormal susceptibility, which indicates a possibility that stress or excessive worry may increase the imbalance among neurotransmitters in the central nervous system and as a result IBS may occur. According to several reports, patients with IBS who were trained for cognitive behavior therapy were able to control the symptoms of stress and anxiety including schoolwork-related problems (38) and relaxation therapy such as meditation, which is helpful to relieve such symptoms (39). Thus, such therapies are expected to be applied to students. In addition, there is a need to formulate an effective plan to relieve the schoolwork stress for the upper grade students who tend to have a higher stress score and anxiety score.

In this study, the incidence rate of IBS reached 8.5% and 17.1% in middle school students and high school students respectively. The incidence rate in middle school students was similar to the rate reported in other studies. But in the case of high school students, it was lower than other studies (19.1 to 25.7%) (17, 22). It may be because the data of high school seniors were excluded from this study. If the data was included, the results may be similar to those of other studies.

Out of demographic characteristics, lower SES was associated with higher prevalence of IBS, but this study was not thought to reflect the difference in IBS prevalence by SES because the number of students included in SES I group was only ten students. Large-scale studies could investigate the prevalence according to SES more accurately.

This study examined prevalence of IBS by subdividing lifestyle factors among risk factors of IBS and found that the groups sleeping for less than six hours a day, liking salty foods and liking fatty foods recorded significantly higher prevalence. According to a study of Lee et al. in 2007, the subjects sleeping for more than six hours a day were found to be more vulnerable to IBS and they reported that the reason was because more sleep time led to less physical activity (22). However, in this study the group sleeping for less than six hours a day showed higher IBS prevalence and recorded higher worry and stress scores. As described before, it was well known that worry and stress were followed by imbalance of neurotransmitters (7, 37). Such imbalance of various neurotransmitters related with worry and stress was considered to work to provoke both of sleep disturbance and occurrence of IBS. The questionnaire used in this study asked only sleep time, so it could not evaluate the quality of sleep. If future study examines the quality of sleep, it will help to assess correlation between sleep disturbance and IBS.

For alcohol-drinking and smoking which have been known to affect gastrointestinal symptoms among lifestyles, the group not drinking alcohol showed a significantly lower prevalence. However, in multivariate regression analysis alcohol-drinking was found not to affect prevalence IBS as an independent variable. That was considered to be because the alcohol-drinking rate was only about 5% not to reflect its effect on the occurrence of IBS and because the subjects might not answer frankly the question about alcohol-drinking which was not allowed. Alcohol-drinking rate and smoking rate of the total subjects of this study were 4.7% and 3%, respectively and the levels were different from those of the survey performed by the Ministry of Health and Welfare in 2007 or 33.6% and 7.9%, respectively. As this study excluded boys, the rates of subjects including male students were expected to become higher to be similar with those of previous reports.

As limitations of this study, it investigated only preference of dietary factors which could influence IBS. Because it did not quantify actual intake, it could not consider the absolute actual intake of the subjects. If a questionnaire survey on an accurate diet is conducted, its results will help to provide appropriate countermeasures through improvement of dietary habits. Second, although it evaluated correlation of IBS with various variables such as lifestyle factors, worry and stress, it could not determine their causal relation because it was a cross-sectional study. Lastly, this study excluded boys and third grade high school girls. Prevalence of IBS of females was reported to be two times higher than that of males and the degree of worry and stress were done to be severer in females than in males, but studies on boys experiencing same stress due to college entrance examination were also considered to be necessary.

Korean adolescents' worries and stress caused by college entrance examination and social expectation can be presented eventually as physical symptoms and especially as IBS or one of gastrointestinal symptoms largely influenced by alterations in the neurotransmitters which are involved in the brain-gut axis. The findings of this study draw a clue that less worry and stress will help decrease IBS symptoms. Additional studies on activities to reduce worry and stress like relaxation therapy and meditation and on improvement of IBS symptoms will make their application to adolescents easier.