A prospective longitudinal 10-year study of schizophrenia's three major factors and depression

This study investigated the nature, independence, and stability of schizoph renia's syndrome factors and depression at 2, 4.5, 7.5 and 10 years post-in dex hospitalization. At the four follow-ups, 71 patients (48 with schizophr enia and 23 with schizoaffective disorder) were assessed for symptoms hypot hesized to constitute the reality distortion, disorganized, and negative fa ctors of schizophrenia. At the last three follow-ups, the patients were als o assessed for symptoms of depression. Factor analyses of schizophrenia sym ptoms revealed more than three syndrome factors at each follow-up. Longitud inally, reality distortion was a stable and relatively independent factor. The negative syndrome was independent but was bifurcated into two dimension s, interpreted as social/emotional withdrawal and diminished movement/expre ssiveness. Although signs of disorganization were not unified or independen t early in schizophrenia's course, speech/thought disorder, disorganized af fect, and poverty of speech content coalesced to form a disorganization fac tor by the 7.5-year follow-up. When depressive symptoms were added to the a nalyses, depression constituted an independent and stable dimension of schi zophrenia over time. Each schizophrenia factor demonstrated a unique longit udinal course. Courses included stable symptom consistency (reality distort ion), evolving symptom convergence (disorganization), and recurrent bifurca tion and symptom instability (the negative syndrome). (C) 2000 Elsevier Sci ence Ireland Ltd. All rights reserved.