Dimensions and subtypes of recent-onset schizophrenia. A longitudinal analysis

A sample of young patients with schizophrenia was studied in a longitudinal design to investigate the stability of an earlier reported four-dimensional symptom model (positive symptoms, negative symptoms, disorganization, and depression). Symptoms were measured in an acute phase soon after hospitalization, in a remitted stage 3 months later, and in a "mixed" phase 1 year after the second assessment. A different factor structure was found at each measurement, but a stable four-dimensional structure could be defined that closely resembled the factor structure of the first assessment. The symptom dimensions were uncorrelated, except disorganization and depression. Whether meaningful subtypes could be defined using statistical criteria also was investigated. With cluster analysis, four subtypes were defined that could be characterized as follows: rapid treatment responders, slower responders, and two relapse groups. Although some indication of the validity of these subtypes was found, it is concluded that there is a high risk of creating artificial boundaries with this approach.