Andreasen, N. C. & Olsen, S. (1982) Negative versus positive schizophrenia. Archives of General Psychiatry, 39, 789–794.
Baldessarini, R. J. & Davis, J. M. (1980) What is the best maintenance dose of neuroleptics in schizophrenia?
Psychiatry Research, 3, 115–122.
Barnes, T. R. E., Curson, D. A., Liddle, P. F., et al (1989) The nature and prevalence of depression in chronic schizophrenic in-patients. British Journal of Psychiatry, 154, 486–491.
Bilder, R. M., Mukherjee, S., Rider, R. O., et al (1985) Symptomatic and neuropsychological components of defect states. Schizophrenia Bulletin, 11, 409–419.
Campbell, P., Taylor, J., Pantelis, C., et al (1990) Studies of schizophrenia in a large mental hospital proposed for closure and in two halves of an Inner London borough served by the hospital. In International Perspectives in Schizophrenia Research: Biological, Social and Epidemiological Findings (ed. Weller, M.), pp. 185–202. London: John Libbey.
Cohen, J. (1960) A coefficient of agreement for nominal scales. Educational and Psychological Measurement, 20, 37–46.
Feighner, J. P., Rubins, E., Guze, S., et al (1972) Diagnostic criteria for use in psychiatric research. Archives of General Psychiatry, 26, 57–62.
Harvey, C. A. (1996) The Camden Schizophrenia Surveys. I: The psychiatric, behavioural and social characteristics of the severely mentally ill in an Inner London health district. British Journal of Psychiatry, 168, 410–417.
Hedderson, J. (1991) SPSS/PC + Made Simple. Belmont California: Wadsworth.
Kay, S. R. & Sevy, S. (1990) Pyramidical model of schizophrenia. Schizophrenia Bulletin, 16, 537–545.
Krawiecka, M., Goldberg, D. & Vaughan, M. (1977). A standardised psychiatric assessment scale for rating chronic psychotic patients. Acta Psychiatrica Scandinavica, 55, 299–308.
Landis, J. R. & Koch, G. G. (1977) The measurement of observer agreement for categorical data. Biometrics, 33, 159–174.
Liddle, P. F. (1987a) The symptoms of chronic schizophrenia. A re-examination of the positive–negative dichotomy. British Journal of Psychiatry, 151, 145–151.
Liddle, P. F. (1987b) Schizophrenic syndromes, cognitive performance and neurological dysfunction. Psychological Medicine, 17, 49–57.
Liddle, P. F. & Barnes, T. R. E. (1990) Syndromes of chronic schizophrenia. British Journal of Psychiatry, 157, 558–561.
Liddle, P. F.
Friston, K. J., Hirsch, S. R., et al (1990) Regional cerebral metabolic activity in chronic schizophrenia. Schizophrenia Research, 3, 23–24.
Liddle, P. F. (1992) Syndromes of schizophrenia on factor analysis. British Journal of Psychiatry, 161, 861.
Liddle, P. F., Frith, C. D., et al (1992) Patterns of cerebral blood flow in schizophrenia. British Journal of Psychiatry, 160, 179–186.
Minas, I. H., Stuart, G. W., Klimidis, S., et al (1992) Positive and negative symptoms in the psychoses: Multidimensional scaling of SAPS and SANS items. Schizophrenia Research, 8, 143–156.
Nie, N. H., Hull, N. C., Jenkins, J. G., et al (1975) Statistical Package for the Social Sciences (2nd edn). New York: McGraw-Hill.
Overall, J. E., Hollister, L. E. & Pichot, P. (1967) Major psychiatric disorders. A four-dimensional model. Archives of General Psychiatry, 16, 146–151.
Peralta, V., De Leon, J. & Cuesta, M. J. (1992) Are there more than two syndromes in schizophrenia? A critique of the positive–negative dichotomy. British Journal of Psychiatry, 161, 335–343.
Rosen, A., Hadzi-Pavlovic, D. & Parker, G. (1989) The Life Skills Profile: A measure assessing function and disability in schizophrenia. Schizophrenia Bulletin, 15, 325–337.
Roy, A. (1982) Suicide in chronic schizophrenics. British Journal of Psychiatry, 141, 171–177.
Soni, S. D., Hollis, S., Reed, P. F., et al (1992a) Syndromes of schizophrenia on factor analysis. British Journal of Psychiatry, 161, 860–861.
Soni, S. D., Mallik, A., Reed, P., et al (1992b) Differences between chronic schizophrenic patients in the hospital and in the community. Hospital and Community Psychiatry, 43, 1233–1238.
Van Der Does, A. J. W., Linszen, D. H., Dingemans, P. M., et al (1993) A dimensional and categorical approach to the symptomatology of recent-onset schizophrenia. Journal of Nervous and Mental Disease, 181, 744–749.
Wing, J. K. (1961) A simple and reliable subclassification of chronic schizophrenia. Journal of Mental Science, 107, 862–875.
Wing, J. K. & Brown, G. W. (1970) Institutionalism and Schizophrenia: A Comparative Study of Three Mental Hospitals 1960–1968. London: Cambridge University Press.
Wykes, T. & Sturt, E. (1986) The measurement of social behaviour in psychiatric patients: An assessment of the reliability and validity of the SBS schedule. British Journal of Psychiatry, 148, 1–11.