M.A. / The overall objective of the global research project of which the present study is a part, is to create a greater awareness and understanding of the association between physiology and psychology, specifically with regard to IBS. Investigations are being conducted into the contribution of such factors as stress, anxiety, depression, somatization, psychopathology. early sexual abuse and physical abuse to the development and management of IBS. The present study aims to assess the incidence of co-morbid psychopathology in patients with IBS as compared to the general population. 1.3.2 Specific Aims. The aim of the present study is to compare the incidence of concurrent psychopathology in a sample of white, female patients, aged from 25-55 years and diagnosed to have IBS, with the incidence of psychopathology in a sample of white female non-IBS controls aged 25-55 years. Of initial concern will be whether the results of this study confirm the findings of the numerous research projects which attest to the high incidence of comorbid psychopathology in patients with IBS (Chaudhary & Truelove, 1962; Liss et al., 1973; Young et al., 1976), or add support to the limited evidence that disputes these claims (Talley, Kramlinger et al., 1993; Thornton, McIntyre et al., 1990). The study then aims to consider whether the variable of gender has a significant effect on the incidence of co-morbid psychopathology in patients with IBS. As will be discussed in Chapter 3, most of the studies do not differentiate between male and female subjects even though this may well prove to be an important determining factor. As mentioned in section 1.2.1, there is a dearth of research in South Africa into IBS and, more specifically, into the incidence of co-morbid psychopathology and IBS. By restricting participants in this study to those of the white race, the aim of this study is to initiate a process in which the incidence of co-morbid psychopathology in IBS patients of all races will be assessed and compared. In addition, the present study aims to assess whether age and level of education are significant variables in determining the incidence of co-morbid psychopathology in patients with IBS. Inter-group comparisons will be made between three groups of patients with IBS divided first according to age and then according to level of education. Finally, the present study aims to be more methodologically sound than certain of the earlier research projects as reported in the literature. As will become clear in Chapters 2 and 3, a common thread running through much of the literature is the concern that the validity of results may be questionable due to methodological flaws in the design of certain research projects. Small sample size has been a problem in some studies (Liss et al., 1973; Young et al., 1976) whilst in others, the absence of a control group has limited the relevance of data (Liss et al., 1973). Furthermore, a diversity of measuring instruments have been used in the past with little if any standardisation or control of specific variables being assessed. The measuring instrument used in this study, namely the Personality Assessment Inventory (PAI), allows for an accuracy and comprehensiveness of assessment not found in many previous studies (see Chapter 6, section 6.2.1.4). The PAI assesses psychopathological trends in personality functioning. The word "psychopathology" will be used in this study as substitute for the phrase "psychopathological trends in personality functioning".