This thesis comprises three main sections: a literature review, research report and a critical appraisal of the research process. The literature reviewed is the current scientific literature relating to shame and guilt. The review attempts to clarify the conceptual confusion regarding shame and guilt and in particular attempts to delineate the distinctions between the two constructs whilst acknowleding the intricate and entwined relationship. The review also attempts to clarify the confusion regarding the role of guilt and its capacity to elicit both adaptive and maladaptive responses according to the way in which it is operationalised and conceptualised. The importance of the relationship between shame, guilt and mental health problems is presented with supporting empirical evidence. It is concluded that a new shame and guilt measure is required to show how shame and the maladaptive and adaptive aspects of guilt can be operationalised. It is hoped that this will enable future researchers to consider incorporating a profile approach to guilt in particular and that clinicians will consider the multiple and complex roles of shame and guilt in relation to psychological symptoms. The research report (Section 2) comprises two studies. Study 1 is the design, development and piloting of the new questionnaire assessing dispositional shame and guilt. The new measure is constructed and validity tested using an inductive approach. Study 2 is the use of the new measure with a forensic clinical sample and the relationship between guilt, shame and psychological symptoms is examined. It is hoped that this study will encourage researchers to locate future investigations within the clinical population. The final section is the researcher's critical appraisal of the research process based on her personal diary. This section is reflective and considers the impact of the research process on the researcher, the highs and lows of the research process and what changes the researcher might make.