This chapter will compare clinical interview and self-report methods of assessment of depressed patients. The two methods overlap to some extent, but each has particular advantages and disadvantages.Spitzer and Endicott [43] have enumerated five major modes of psychiatric rating: (1) The patient may fill out a self-report questionnaire; (2) a relative or other informant may fill out a questionnaire reporting on the patient; (3) a professional, most commonly a nurse, may observe the patient in a naturalistic setting, such as a hospital ward; (4) a professional may interview an informant; and (5) a professional may interview the patient and rate both what the patient tells him and what he has observed.The major division is between the first method, the self-report questionnaire, and the remaining methods, which depend on an outside observer: a relative, nurse, or psychiatrist at interview. Most studies in depression have, in fact, contrasted the self-report method with the interview, incorporating verbal material and observed behaviour, the usual method of the psychiatrist-administered rating scale.
Sources of DiscrepancyThere are easily identifiable sources of potential discrepancy both in self-report and in interview scales. First some aspects of psychopathology cannot readily be assessed by the self, since they are mainly apparent to others. These include purely observational elements such as appearance of depression and psychomotor retardation. The extent to which this gap in assessment actually matters will depend on the extent to which the observational elements behave differently to subjective feelings. In addition, self-report scales cannot tap fully those aspects, such as delusions, hallucinations, and hypochondriacal overconcern, into which the patient does not have insight. Carefully framed questions can elicit some aspects of the phenomena, without clearly distinguishing the reality-based from the delusional.A possibility which has tended to be neglected is the presence in self-report symptom questionnaires of pencil-and-paper answering habits or response sets which may distort answers. One such set is acquiescence or yea-saying [10] -the tendency to respond affirmatively to all questions, irrespective of content. Another response set, social desirability [16], involves the tendency to select a socially acceptable response rather than the true one.
N. Sartorius et al. (eds.), Assessment of Depression