A recent study by Jim van Os and his colleagues provides some empirical support for this approach. Using his sample of over 700 psychotic patients, van Os assessed the power of categories (DSM-III-R diagnoses) and symptom dimensions to predict illness course, employment history, suicidal behaviour, the patients’ perceived quality of life, and a number of other variables. For nearly all of these, the dimensions were more powerful predictors than the categories.60 None of these strategies has received
