The primary aim of the NormQuest study described in this thesis was to generate evidencebased, reference values for 19 self-report and observational questionnaires. The focus was on questionnaires... Show moreThe primary aim of the NormQuest study described in this thesis was to generate evidencebased, reference values for 19 self-report and observational questionnaires. The focus was on questionnaires measuring mood, anxiety, and somatoform (MAS) disorders used in Routine Outcome Monitoring (ROM). The set of cut-off values of the ROM reference group (__healthy__) can be used in specialized mental health care by therapists to support the decision whether a patient is sufficiently recovered to be considered as a member of the healthy population, and no longer as a member of the patient population. These reference values are suitable as decision support for referral back to primary care physicians. Additionally, the set of the ROM patient group (__clinically ill__) cut-off values can be used by primary care physicians as decision support for referral to the specialized mental health care. To allow determination of cut-off points for skewed distributions, percentile scores were used. In addition, we assessed the discriminative power of the questionnaire scores by means of Receiver Operating Characteristics (ROC) analyses. Finally, we calculated reference values in separate strata of gender and age. The secondary aim of the NormQuest study concerned the need for the development of public domain questionnaires. In the NormQuest study, the generic Symptom Questionnaire-48 (SQ-48), aimed at broad applicability in patients with MAS disorders, was developed. Also, for the SQ-48 reference values were calculated Show less
Research into the relation between psychopathology and etiological factors has not yet resulted in clear findings. One of the probable causes is that most researchers use the categorical DSM-IV... Show moreResearch into the relation between psychopathology and etiological factors has not yet resulted in clear findings. One of the probable causes is that most researchers use the categorical DSM-IV Classification of mental disorders. A dimensional system has several advantages compared to categorical systems: comorbidity, lack of diagnostic agreement and arbitrary nature of used boundaries are no longer a problem. Our aim was to develop a model with dimensions that can adequately describe patients with mood- and anxiety disorders. This project used data collected through Routine Outcome Monitoring (ROM), a monitoring system for patient care. First, we validated a Dutch adaptation of an instrument based on the tripartite model. Next, we formulated an extension of this model with 5 dimensions. Consequently we presented a second model with 6 dimensions: feelings of worthlessness, fatigue, somatic arousal, anxious apprehension, phobic fear and tension. We used several analysis techniques to create a valid and reliable dimensional model. Each individual factor and the total of factors can be regarded as unidimensional measurement scales. This model can describe the clinical state of patients more specifically than the tripartite model, and can be used in subsequent research into etiological factors of psychopathology (e.g. endophenotype, genotype, trauma's, personality). Show less
