To examine the relationship between patient self-ratings and physician ratings of general health, depression, and anxiety and patient and physician ratings in comparison to Diagnostic Interview Schedule (DIS) diagnoses of depression and anxiety. Observational study. A general medical outpatient clinic. Clinic attendees. Consecutive clinic attendees on randomly selected days completed a self-reported screening questionnaire for hypochondriasis, composed of the Whiteley Index and the Somatic Symptom Inventory. A random sample of patients (N = 79), 95% of whom had scores below the cutoff for hypochondriasis (n = 75) and 5% of whom had scores at or above the cutoff for hypochondriasis (N = 4), returned at a later date to complete a research battery consisting of self-reported questionnaires, structured and semistructured interviews, and a structured interview for diagnoses of anxiety and depression based on the DIS, which used criteria from the Diagnostic and Statistical Manual of Mental Disorders, Revised Third Edition. Responses to questionnaires and interviews. Agreement between patients and physicians was statistically significant concerning patients' physical health, depression, and anxiety. Based on one question, both physicians' and patients' ratings of depression and anxiety compared favorably with DIS diagnoses. By means of receiver operating characteristics analysis, values for the areas under the curve and their SEs were as follows: for depression, 0.789 +/- 0.075 for patient self-ratings and 0.825 +/- 0.054 for physician ratings; for anxiety, 0.734 +/- 0.058 for patient self-ratings and 0.667 +/- 0.065 for physician ratings. One simple question about a patient's status with respect to depression or anxiety is sufficient to detect these disorders with high sensitivity and specificity, yielding values comparable to those yielded by instruments consisting of many items. Asking patients to rate their own levels of depression and anxiety may constitute one portion of the family physician's diagnostic assessment for these conditions.