Relapse: a reappraisal of assessment of outcome in schizophrenia.

Although measurement of the course of schizophrenic disorder has relied heavily on the concept of relapse, a review of the literature reveals a paucity of clear definitions of relapse. In most research studies, the assessment of relapse has been made on the basis of clinical judgment, with little attempt to apply more rigorous psychometric standards. The limitations of this approach are discussed and several possible improvements are suggested. These include: operational definitions that specify the qualitative, quantitative, and temporal characteristics of symptomatic exacerbation; avoidance of potentially confounding social variables; and the use of standardized rating scales and target symptoms.