Psychiatry - July 2008 - (Page 54)

status (positively or negatively) in SFAS. Of the 794 SFAS candidates who were given the study recruitment speech, 774 candidates enrolled in the study. Thus, the refusal rate was three percent. Information on the 20 individuals who refused to participate in the study was not available to the research team. Participants. Of the 794 candidates approached, 774 (97%) active duty male soldiers (mean age 26, SD=4) agreed to participate in the study. All participants were enrolled in a US Army SFAS program. The participants’ mean years of service in the Army was 4.9 (SD=3.2). Two-hundred eighty soldiers (36%) were married, 403 (52%) soldiers were single, and 86 (11%) soldiers were divorced. Eighty-six percent or 677 candidates were enlisted and 110 (14%) were officers. Procedure. After providing informed consent, participants completed the self-report portion of the Clinician Administered Dissociative Symptom Scale (CADSS). The CADSS is a reliable, valid, self-report instrument designed to assess state symptoms of dissociation in response to a specified stressor.14 Subjects were instructed to complete the CADSS using the week previous to enrollment in the course as their reference point. Subjects were instructed to inform the research team (orally and in writing) if during the previous week they had experienced any traumatic or highly stressful events. We did not include the clinician-observer component of the CADSS given the low intercorrelation coefficients for this component. After completing the CADSS, participants commenced participation in SFAS. Data analysis. In order to test the hypothesis that symptoms of dissociation would be significantly related to success or failure in SFAS, the following variables were created: total CADSS scores (the sum of individual CADSS items); classification scores indicating 54 Psychiatry 2008 [ J U L Y ] whether or not subjects reported symptoms of dissociation at baseline (1=yes; 0=no); and two additional classification scores designed to classify subjects in a binary fashion based on whether or not their CADSS total score was greater than, at, or below a specified value (less than 5; equal to, or greater than, 5; less than 11; equal to or greater than 11). These classification cut-off points were selected based on the distribution of responses from subjects in this study and on the mean pre-stress CADSS dissociation scores noted in our previous studies.15 Chi-squared analyses were performed to test whether subjects endorsing baseline symptoms of dissociation (any, greater than 5 points, greater than 11 points) were more likely to fail SFAS compared to peers who did not report such symptoms. Receiver operator characteristics (ROC) curves. ROC curves were created by using the CADSS baseline total score (the test variable) in order to predict outcome in the SFAS program (the state variable, where 1= failed SFAS). ROC graphs were created for the group as a whole and for the sub-group of subjects whose CADSS score was 1 or greater. For both ROC graphs, the area under the curve as well as coordinate points for the curve were calculated (SPSS 11.5). The null hypothesis assumption was that the true area under the curve equals 0.5. With regard to the parameters for the standard distribution of error, the distribution assumption was nonparametric and the confidence interval 95 percent.16 Although this method is also a regression model, it offers an advantage over the logistic regression format in that a classification table corresponding to specific scores on the CADSS and to the likelihood of success or failure in the course is possible. RESULTS Of the 774 who participated in the study and in SFAS, 318 successfully passed the course; 456 candidates did not. The mean CADSS score at baseline was 2.39 (SD=4.5; range=44). The distribution was not normal (skewness 3.30). Of the 774 subjects, 425 subjects (55.0%) did not endorse any symptoms of dissociation at baseline; 349 subjects (45.0%) endorsed such symptoms. As shown in Tables 1, 2, and 3, the pass rates in SFAS were significantly different between the group of candidates who reported dissociation and those who did not (Score of 1 or greater on the CADSS versus CADSS score of zero: ChiSquare=4.5; df=1; asymptotic significance [asymp. sig.] (2-sided) p<0.035; Fisher’s Exact Test, Exact Significance: p<0.04 (2-sided); p<0.021 (1-sided); Score of five or more on the CADSS versus a score of less than 5 on the CADSS: ChiSquare=9.3; df=1; asymp. sig. (2sided) p<0.002; Fisher’s Exact Test, Exact Significance: p<0.002 (2-sided); p<0.001 (1-sided); Score of 11 or more on the CADSS versus a score of less than 11: ChiSquare=10.7; df=1; asymp. sig. (2-sided) p<0.001; Fisher’s Exact Test, Exact Significance: p<0.001 (2-sided); p<0.001 (1-sided). ROC curve data. When an ROC curve is created, the area may take values between 1 and zero. A value of 1 or zero would indicate that the test is always right or always wrong, respectively. If the test performs no better than chance at detecting the state variable (for example, failure in SFAS), the area under the curve would be 0.5. Using the variable “total dissociation score” as the “test variable” and “status” as the “state variable” (value of the state variable=failure in SFAS), ROC analyses indicated that the area under the curve was 0.6 (nonparametric standard of error=0.021); p<0.01. Thus, the total dissociation score performed better than chance at predicting likelihood of failure at SFAS. Table 4 lists the coordinate points of the ROC analysis and indicates, for a given score on the CADSS, the probability of being

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Psychiatry - July 2008 Editor's Message Editorial Advisory Board Contents PsychRx Letters to the Editor Reliability of Diagnoses: Do Psychiatrists Use Structured Interviews In Real Clinical Settings? Trend Watch: Use of Atypical Antipsychotics in the Elderly Review: The Struggle for Mental Healthcare in New Orleans-One Case at a Time Psychotherapy Rounds: Psychotherapeutic and Adjuntive Pharmacologic Approaches to Treating Posttraumatic Stress Disorder Original Research: Baseline Dissociation and Prospective Success in Special Forces Assessment and Selection Commentary: Performance-Enhancing Drugs: Where Should the Line Be Drawn and By Whom? Commentary: Psychiatric Diagnosis and the Pathlogist's View of Schizophrenia Journal Watch Classified Advertising Information for Authors

Psychiatry - July 2008

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