The Psychiatric Diagnostic Screening Questionnaire
Psychiatric Diagnostic Screening Questionnaire
by Mark Zimmerman, M.D. MANUAL
12031 Wilshire Boulevard Los Angeles, California 90025-1251
Mark Zimmerman, M.D.
Western Psychological Services
The Psychiatric Diagnostic Screening Questionnaire (PDSQ) is a self-report instrument designed to screen for the DSM-IV (Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition; American Psychiatric Association, 1994) Axis I disorders most commonly encountered in medical and outpatient mental health settings. Over the course of 10 years and more than 3,000 administrations, the instrument has been demonstrated to be convenient and reliable, and it has been validated against diagnostic criteria and standard interview-derived diagnoses. Because it is brief and yet addresses multiple syndromes, the PDSQ allows practitioners to improve clinical efficiency by routinely taking diagnostic comorbidity into account while adding only minimally to administrative time burdens. This instrument is short enough to be completed by patients before their initial diagnostic evaluation and to be rapidly scored and reviewed by a clinician or office worker, but is also comprehensive and long enough to be psychometrically sound. The PDSQ is the first self-administered questionnaire explicitly developed to assess the symptoms of several DSM-IV Axis I disorders in psychiatric patients. Other multidimensional questionnaires, such as the Minnesota Multiphasic Personality Inventory-2 (Butcher, Graham, Williams, & Ben-Porah, 1990) and the Millon Clinical Multiaxial Inventory-III (Millon, 1994) have been used as diagnostic aids; they were not, however, designed to be congruent with the current diagnostic nomenclature. Moreover, these inventories are too long, and their scoring too time consuming, to be routinely completed and scored in an office waiting area before the initial evaluation. One self-report instrument developed subsequent to the PDSQ (Spitzer, Kroenke, & Williams, 1999) was created for use in only primary care settings.
home and bring it with them to the office. The organization of the PDSQ facilitates rapid hand-scoring, which makes it feasible for use in routine clinical practice. PDSQ item responses can be scored to obtain subscale scores in the 13 areas listed in Table 1: Major Depressive Disorder, Posttraumatic Stress Disorder, Bulimia/BingeEating Disorder, Obsessive-Compulsive Disorder, Panic Disorder, Psychosis, Agoraphobia, Social Phobia, Alcohol Abuse/Dependence, Drug Abuse/Dependence, Generalized Anxiety Disorder, Somatization Disorder, and Hypo chondriasis. The PDSQ Total score (the sum of all subscale scores) can be used as a global measure of psychopathology. Six of the items on the Major Depressive Disorder subscale measure suicidal ideation. Follow-up Interview Guides (WPS Product No. W-385D), sheets adapted from Zimmerman (1994), are available for each syndrome covered by the PDSQ. These guides provide prompts for asking follow-up questions related to w diagnostic criteria, and provide a place to document details relevant to diagnostic information gained from the PDSQ and follow-up interview. A sample of the guide for Table 1 PDSQ Subscales
General Description The PDSQ was designed to be administered and scored in the office before the initial diagnostic interview. The scale has 125 yes/no items (111 numbered items, two of which have multiple parts), and takes approximately 15 to 20 minutes to complete. Patients can complete it in the waiting area before their appointments or they can take it at
No. of items
Major Depressive Disorder Posttraumatic Stress Disorder Bulimia/Binge-Eating Disorder Obsessive-Compulsive Disorder Panic Disorder Psychosis Agoraphobia Social Phobia Alcohol Abuse/Dependence Drug Abuse/Dependence Generalized Anxiety Disorder Somatization Disorder Hypochondriasis PDSQ Totala
21 15 10 7 8 6 11 15 6 6 10 5 5 125
a Includes the several lettered parts (a through h), of Items 69 and 77 on the Agoraphobia and Social Phobia subscales, respectively.
Major Depressive Disorder is provided in the back of this manual. During development with outpatients in a clinical mental health setting, the average internal consistency value for the PDSQ subscales was estimated to be .85 (median = .88; range .66 to .94), the average test-retest reliability was estimated to be .81 (median = .82; range .61 to .93), and the average validity coefficient was estimated to be .64. The diagnostic screening performance of the PDSQ is associated with an average AUC (area under the curve) value of .85 (range .76 to .92). When the sensitivity of cutting scores for the purpose of clinical screening is set at 90% (that is, 90% of true cases identified), (a) the PDSQ subscales’ average negative predictive value (the amount of all identified non-cases that are true non-cases) is 97%, and (b) the false positive rate is 34% (meaning 34% of all identified cases are actually non-cases, although they may actually display clinically important characteristics). For a more detailed presentation and discussion of these PDSQ characteristics, refer to chapters 4 and 5 of this manual.
Uses and Limitations The PDSQ is intended to be used in any clinical or research setting where screening for psychiatric disorders is of interest. Such settings include those where mental health and medical primary care services are provided, as well as those where clinical drug trials or clinical program evaluations are carried out. It can be administered and scored by any appropriately trained and supervised technician, but ultimate responsibility for the clinical interpretation of PDSQ results should be undertaken only by a professional with sufficient psychometric and clinical training to understand and make effective use of the support provided in this manual. Such an individual will understand the characteristics and use of cutting scores and the appropriate way to incorporate critical item content into the interpretation of scale scores. He or she should also have enough experience with the presentation of test results to adequately respond to any questions posed by the test taker about the PDSQ or its interpretation. As with any clinical measure, PDSQ results should be verified whenever possible against all available information, including the results of patient interviews, clinical history, professional consultations, service agency records, and the results of additional psychological tests.