A dimensional and categorical approach to the symptomatology of recent-onset schizophrenia

Sixty-five patients with recent-onset schizophrenia were assessed with two widely used symptom scales, the Brief Psychiatric Rating Scale-Expanded (BPRS-E) and the Psychiatric Assessment Scale (Manchester scale). Principal components analysis of the BPRS-E scores yielded a four-dimensional structure: positive symptoms, negative symptoms, disorganization, and depression. With the Psychiatric Assessment Scale, three dimensions were found: the positive symptoms (delusions, hallucinations) and disorganization (incoherence) appeared in one dimension. A categorical analysis resulted in predominantly positive, negative, and disorganized clusters, but more than half of the sample could not be allocated to any of these groups.