Comparability of Telephone and Face-to-Face Interviews in Assessing Patients with Posttraumatic Stress Disorder

Abstract

Structured clinical interviews are very important in the area of mental health research and services. Prior research comparing the reliability and validity of face-to-face and phone interviews has found high levels of agreement. This project compared the results of face-to-face and phone interviews for two widely used measures: The Clinician-Administered PTSD Scale (CAPS) for assessing posttraumatic stress disorder diagnostic status and symptom severity and the Hamilton Rating Scale for Depression (Ham-D) to determine the severity of major depressive disorder. Subjects were 34 veterans recruited from applicants to the PTSD Assessment and Intervention program at the Cincinnati VA Medical Center. Order of interview (in-person or phone) was determined using random assignment within a counterbalanced framework. After attaining satisfactory levels of interrater reliability, four clinicians independently and blindly evaluated the subjects. Pearson correlation coefficients between face-to-face and phone interviews revealed high consistency (CAPS r = 0.745, HAM-D r = 0.748). The level of agreement between the two methods was 82% for the CAPS and 85% for the HAM-D. Diagnostic thresholds for the CAPS and HAM-D, after adjusting for the interview order and time elapsed between interviews, did not differ between the two groups (p = 0.31 for the CAPS and p = 0.96 for the HAM-D). High levels of agreement were achieved between the two methods (kappa = 0.75 for the CAPS using a cutoff of 65 and 0.70 for the HAM-D). The high sensitivity, specificity, and predictive values support the reliability of the phone-interview method. Phone interviews are a reliable method of interviewing for use in assessing patients for posttraumatic stress disorder and major depressive disorder.