The Dissociative Experiences Scale: Further replication and validation.

The purpose of the present study was to provide further evidence in support ofthe validity ofthe Dissociative Experiences Scale [DES] as a reliable measure of dissociative psychopathology. The DES was administered to 259 college students, 33 patients with multiple personality disorder (MPD), and 29 patients with a dissociative disorder not otherwise specified (DDNOS). The inter-rater reliability for the DES scoring procedure was excellent (coefficient of absolute agreement =. 96; coefficient ofrelative agreement =. 99). The test retest reliability ofDES scores (within approximately one month) was also excellent (coefficient ofabsolute agreement =. 93; coefficient ofrelative agreement=.96) and suggests that DES total scores are temporally stable and similar in absolute value across testings. Finally, the internal consistency of DES scores was also very high (alpha for students=.93; alpha for MPD patients =.94; alpha for DDNOS patients=.94; alpha for the combined total sample=. 95). Both MPD (meanDESscore=55.0)andDDNOSpatients(meanDESscore=40.8) earned significantly higherDESscores than students (mean DESscore =23.8). In addition, MPD patients earned significantly higher DES scores than DDNOS patients. The results of the present study also suggest that a DES cutoffscore of45 to 55 maximizes the probability of correctly classifYing students from dissociative disorder patients (87%) while minimizing the rates offalse positive (2 to 6%) and false negative errors (7 to 11 %). Suggestions for further validation research are also made. The Dissociative Experiences Scale (DES: Bernstein & Putnam, 1986) is a brief, 28 item, self-report inventory of both normal and abnormal experiences. The DES was developed "to offer a means of reliably measuring dissociation in normal and clinical populations" (Bernstein & Putnam, 1986, p. 727). Preliminary psychometric data reported by the authors of the scale indicated that summary scores were temporally stable (r [after 4 to 8 weeks] =.84) and successfully discriminated patients with multiple personality disorder (MPD) from normals and other pathological groups (Bernstein & Putnam, 1986). Two laboratories have since independently confirmed the discriminant validity of the DES as a measure ofdissociative psychopathology relative to different kinds of normal comparison groups. For example, Ross, Norton, and Anderson (1988) reported that the median DES score of 17 MPD patients was 40.7. Although this score was significantly lower than the median DES score of 57.06 originally reported by Bernstein and Putnam (1986) for their 20 MPD subjects, it was still significantly higher than the median score of 4.9 observed for their normal subjects (medical students). In a later study, Ross, Ryan, Anderson, Ross, and Handy (1989) reported that normal median DES scores could vary from a low of 4.8 (for elderly subjects), 7.9 (for college student subjects), to a high of 17.7 (for adolescent subjects). DES scores were inversely related to age and no significant differences were observed for sex. Ensink and van Otterloo (1989) reported that 7 MPD patients earned a median DES score of55.4while 13 patients with a diagnosis of Dissociative Disorder not otherwise specified (DDNOS) earned a median DES score of40.7. The median DES scores for botl1 dissociative groups, however, we;e significantly higher than the median DES score of 16.3 for 80 psychology students. Collectively, the findings from three different laboratories have each demonstrated that patients with dissociative psychopathology (either MPD or DDNOS) earn significantly higher DES scores than various normal comparison groups. However, there was significant variation among DES scores within both the dissociative (range ofmedian DES scores=40.7 to 57.06) and normal groups (range of median DES scores=4.38 to 17.7). This variation makes it difficult to