The categorical versus dimensional assessment controversy in the sociology of mental illness.

This paper reviews the sociological controversy over using categorical versus dimensional assessments in the study of psychological distress. The preference of sociologists for dimensional assessments is traced to two assumptions: (1) that the associations of predictors with psychological distress syndromes are most accurately operationalized by using dimensional measures; and (2) that no true discrete mental illnesses can reasonably be inferred to exist that would justify the creation of dichotomous measures. Methods are described in this paper to test both assumptions. An argument is made that the first assumption is the critical one and that dimensional analysis is useful only when it can be demonstrated that the associations of predictors with dimensional scores are constant throughout the relevant dimensional severity range. The paper closes with an argument for the tandem use of categorical and dimensional assessments in future sociological research.