Abstract
Objective: The schizophrenia and other non-affective disorders categories listed in the DSM-IV, are currently under revision for the development of the fifth edition. The aim of the present study is to demonstrate the validity of these categories by investigating possible differences between diagnostic patient subgroups on various measures.
Methods: 1064 patients with a diagnosis of non-affective psychosis (schizophrenia N = 731 (paranoid type 82%), schizoaffective N = 63, schizophreniform N = 120, psychosis not otherwise specified/brief psychotic disorder N = 150) participated in this study. Dependent variables were demographic and clinical characteristics, severity of psychopathology, premorbid and current functioning, and indicators of quality of life.
Results: Within the diagnostic group of schizophrenia, no significant differences were observed between paranoid schizophrenia, disorganized, and undifferentiated schizophrenia. Patients with schizophrenia experienced more severe psychopathology and had poorer levels of current functioning compared to patients with psychosis not otherwise specified or brief psychotic disorder. Differences between schizophrenia and schizoaffective disorder were less clear.
Conclusion: Our results do not support the validity of schizophrenia subtypes. Schizophrenia can be distinguished from brief psychotic disorder and psychotic disorder not otherwise specified. These findings may fuel the actual DSM-V discussion.
Key words::
Acknowledgements
GROUP contributors
Amsterdam
Academic Medical Centre: S.E. van den Berg, C.L.A. Schroeder, R. van der Valk, N. Dekker, C.J. Meijer, N. Korver, L.N. Boyette, J. Meijer, D. van Dam; GGZ Ingeest: I. de Rijke, S. Huinink, R.J. de Vries, M. Jansen, D. Bos; Arkin: W.P. Hoen, E.M. te West, S.H.J. Groeneveld, E.M. Vergunst, M.Swets, S. Vothknecht, I. Poleacov; Dijk en Duin: D. van Dijk, S. de Metz, M.T. Hasty, G. Geertsa, P.M. de Baaij, A. Metzger; Erasmus University Medical Centre: N.J.M. van Beveren, M. Baldini; GGZ INgeest: F.D. Grimbergen, M.A.M. Boerma, C. Agsteribbe; GGZ Noord Holland Noord: H.P. Wisman, M.A.H. Monden, M.M. Bosman, M. van Dijk; Rivierduinen: R. Klaassen, T.van der Tang, B. Luteijn, H. Winkel, H. Weisz, A.C.P. Strater, A. Landman, M. Vorstenbosch.
Maastricht
D. Op ‘t Eijnde, K. Lenders, S. Loyen, R. Roberts, K. Sweers, H. Gielen, N. Soons, A. Hintzen, V. Habets, I. Riské, C. Vossen, E. Martens, S. Apers, L. Wijnhoven, E. Konings, T. Lataster, M. Lardinois, D. Versmissen, C. Simons, M. van der Werf, P. Habets, S. Pfeifer, E. de Loore, M. Heins, M. Oorschot, M. Meys, M. Dietvorst, C. van Zelst, I. Crolla, R. Mengelers, F. van Goethem, W. Beuken, D. Byniam, T. Driesen, M. Marcelis, G. Driessen, A. Shazad, R. van Winkel, C. Henquet, G. Kenis, P. Delespaul.
Utrecht
Academic Medical Centre: P. Anema, E.M.J. van Baaren, S.C. Bakker, H.B.M. Boos, E. Caspers, E.M. Derks, S. van Hemert, A. Hemkes, R. Hijman, M. van Leeuwen, J.E.H. Machielsen, R.A. Ophoff, M. Rais, M. Salden, H. van Someren, E. Strengman, M. Vleesschouwer; Symfora: M. van Beek, P.N. van Harten, J.P.F. Koning, W. Schep; Meerkanten: M.G. Vollema, P. Prins, T. Viester; Altrecht: A. Akdeniz, K. Verweij, N. Kaymaz; RIAGG Amersfoort: F. v.d. Heuvel, B. v.d. Goot; Delta: J.E. Hovens, A.J.M. Loonen.
Groningen
UMCG Groningen: J. Bous, M. Veenstra, E. van ‘t Hag, P.J. Quee, F.J. Nienhuis, H.G.O.M. Smid, E. Veermans, A.A. Bartels; Lentis: F. Duijndam, T. Lugtenberg, H. Knegtering; GGZ Friesland: W. Blaauw, A. Wunderink; GGZ Drenthe: K.P. Touw, J. Arends, C.J. Slooff; Dimence: J. Brilman, M. Schomaker, M van Wijk, A. Wessels; Mediant GGZ Twente: E. Vroom, K. Meijerink; GGNet: I. Bogert, W. Janssen, H. de Berk, E.O. Noorthoorn; Parnassia: H. Ising, J.D. Blom, M. van der Gaag; De Grote Rivieren: G. Mensen, R. van der Snoek, R. Smit, G. Faber.
Declaration of interest:
The GROUP project was supported by a grant from the Netherlands Organization for Health Research and Development (ZonMw), within the Mental Health Program (project number: 10.000.1001). ZonMw had no further role in study design, in the collection, analysis and interpretation of data, in the writing of the report, and in the decision to submit the paper for publication. All other authors declare that they have no conflicts of interest. The authors alone are responsible for the content and writing of the paper.