DEVELOPMENT, RELIABILITY, AND VALIDITY OF A DISSOCIATION SCALE (DEREALIZATION, DEPERSONALIZATION, TEST CONSTRUCTION)

Dissociation is a lack of the normal integration of thoughts, feelings, and experiences into the stream of consciousness and memory. The phenomenon occurs to some degree in mentally normal individuals and is thought to be more prevalent in persons with major mental illnesses. The Dissociative Experiences Scale (DES) has been developed to offer a means of reliably measuring dissociation in normal and clinical populations. Scale items were developed using clinical data and interviews, scales involving memory loss, and consultations with dissociation experts. Pilot testing was done to refine the wording and the format of the scale so that it would be more comprehensible to subjects. The scale is a 28 item, self-report questionnaire. Subjects were asked to make slashes on 100 mm lines to indicate where they fall on a continuum for each question. In addition, demographic information (age, sex, occupation, and level of education) was collected so that the connection between these variables and scale scores could be examined. The mean of all item scores ranges from 0 to 100 and is called the DES score. The scale was administered to between 10 and 39 subjects in each of the following populations: normal adults, normal late adolescent college students, and persons suffering from alcoholism, agoraphobia, phobic-anxious disorders, post-traumatic stress disorder, schizophrenia, and multiple personality disorder. Reliability testing of the scale showed that the scale had good test-retest reliability and good split-half reliability. Item-scale score correlations were all significant, indicating good internal consistency. A Kruskal-Wallis test and post-hoc comparisons of the scores of the eight populations gave evidence of the scale's criterion-referenced validity. The scale was able to distinguish fairly well between subjects with dissociative disorders (i.e. multiple personality) and all other subjects. A cutting score of 37 maintained the false positive error rate at 5% while correctly identifying 75% of the subjects with dissociative disorders.