Bartko, G., Herczeg, I. & Zador, G. (1988). Clinical symptomatology and drug compliance in schizophrenic patients. Acta Psychiatrica Scandinavica 77, 74–76.
Bland, R. (1982). Predicting the outcome in schizophrenia. Canadian Journal of Psychiatry 27, 52–62.
Bland, R. & Orn, H. (1980). Schizophrenia: Schneider's first rank symptoms and outcome. British Journal of Psychiatry 137, 63–68.
Brockington, I., Kendell, R. E. & Leff, J. (1978). Definitions of schizophrenia: concordance and prediction of outcome. Psychological Medicine 8, 387–398.
Brockington, I., Roper, A., Edmunds, E., Kaufman, C. & Meltzer, H. (1992). A longitudinal psychopathological schedule. Psychological Medicine 22. 1035–1043.
Brown, K. &White, T. (1992). Syndromes of schizophrenia and some clinical correlates. British Journal. of Psychiatry 161, 317–322.
Buchanan, A. (1992). A two-year prospective study of treatment compliance in patients with schizophrenia. Psychological Medicine 22, 787–797.
Carpenter, W., Bartko, J., Strauss, J. & Hawk, A. (1978). Signs and symptoms as predictors of outcome: a report for the international pilot study of schizophrenia. American Journal of Psychiatry 135, 940–945.
Castle, D. & Murray, R. (1991). The neurodevelopmental basis of sex differences in schizophrenia. Psychological Medicine 21, 565–575.
Castle, D., Phelan, M., Wessely, S. & Murray, M. (1993). Which schizophrenics are not admitted at first psychiatric contact? An analysis of 484 patients. Schizophrenia Research 9, 130.
Cloninger, C., Martin, R., Guze, S. & Clayton, P. (1985). Diagnosis and prognosis in schizophrenia. Archives of General Psychiatry 42, 15–25.
Costello, C. (1992). Research on symptoms versus research on syndromes. Arguments in favour of allocating more research time to the study of symptoms. British Journal of Psychiatry 160, 304–308.
David, T. (1990). Insight and psychosis. British Journal of Psychiatry 157, 774–775.
Dunn, G., Sham, P. & Hand, D. (1993). Statistics and the nature of depression. Psychological Medicine 23, 871–889.
Endicott, J., Nee, J., Cohen, J., Fleiss, J. & Simon, R. (1986). Diagnosis of schizophrenia. Prediction of short-term outcome. Archives of General Psychiatry 43, 13–19.
Everitt, B., Gourlay, A. & Kendell, R. E. (1971). An attempt at validation of traditional psychiatric syndromes by cluster analysis. British Journal of Psychiatry 119, 399–412.
Fenton, W. & McGlashan, T. (1991). Natural history of schizophrenia subtypes. II. Positive and negative symptoms and long-term course. Archives of General Psychiatry 48, 978–986.
Fleiss, J., Gurland, B. & Cooper, J. (1971). Some contributions to the measurement of psychopathology. British Journal of Psychiatry 119, 647–656.
Hamilton, M. (1960). A rating scale for depression. Journal of Neurology, Neurosurgery and Psychiatry 23, 56–62.
Hirsch, S. (1991). Affective symptoms in schizophrenia, basic, prodromal and residual: implications for a functional approach to diagnosis. In Concepts of Mental Disorder: A Continuing Debate (ed. Kerr, A. and McClelland, H.), pp. 66–74. Gaskell: London.
Huber, G., Gross, G., Schüttler, R. & Linz, M. (1980). Longitudinal studies of schizophrenic patients. Schizophrenia Bulletin 6, 592–605.
Iager, A. C., Kirch, D. G. & Wyatt, R. J. (1985). A negative symptom rating scale. Psychiatry Research 16, 27–36.
Jablensky, A., Schwartz, R. & Tomov, T. (1980). WHO collaborative study of impairments and disabilities associated with schizophrenic disorders. A preliminary communication. Objective and methods. Acta Psychiatrica Scandinavica, suppl. 285, 152–163.
Johnstone, E. C., Crow, T. J., Frith, C. D. & Owens, D. G. (1988). The Northwick Park ‘functional’ psychosis study: diagnosis and treatment response. Lancet ii, 119–125.
Kay, S. & Murrill, L. (1990). Predicting outcome of schizophrenia: significance of symptom profiles and outcome dimensions. Comprehensive Psychiatry 31, 91–102.
Kendell, R. (1975). The Role of Diagnosis in Psychiatry. Blackwell: Oxford.
Kendell, R., Brockington, I. & Leff, J. (1979). Prognostic implications of six alternative definitions of schizophrenia. Archives of General Psychiatry 35, 25–31.
Leff, J., Sartorius, N., Jablensky, A., Korten, A. & Ernberg, G. (1992). The International Pilot Study of Schizophrenia: five year follow-up findings. Psychological Medicine 22, 131–145.
Lenzenweger, M., Dworkin, R. & Wethington, E. (1991). Examining the underlying structure of schizophrenic phenomenology: evidence for a three-process model. Schizophrenia Bulletin 17, 515–524.
Liddle, P. (1987 a). The symptoms of schizophrenia. A re-examination of the positive–negative dichotomy. British Journal of Psychiatry 151, 145–151.
Liddle, P. (1987 b). Schizophrenic syndromes, cognitive performance and neurological dysfunction. Psychological Medicine 17, 49–57.
Liddle, P., Friston, K., Frith, C., Hirsch, S., Jones, T. & Frackowiak, R. (1992). Patterns of cerebral blood flow in schizophrenia. British Journal of Psychiatry 160, 179–186.
McEvoy, J., Freter, S., Everett, G., Geller, J., Appelbaum, P., Apperson, J. & Roth, L. (1989). Insight and the clinical outcome of schizophrenic patients. Journal of Nervous and Mental Disease 177, 48–51.
McGlashan, T. (1981). Does attitude toward psychosis relate to outcome? American Journal of Psychiatry 138, 797–801.
McGlashan, T. (1988). A selective review of recent North American long-term follow-up studies of schizophrenia. Schizophrenia Bulletin 14, 515–542.
McGuffin, P., Farmer, A. E. & Harvey, I. (1991). A polydiagnostic application of operational criteria in psychotic illness: development and reliability of the OPCRIT system. Archives of General Psychiatry 48, 764–770.
Manley, B. (1986). Multivariate Statistical Methods. Chapman & Hall: London.
May, P., Tuma, H. & Dixon, W. (1981). Schizophrenia, a follow-up study of the results of five forms of treatment. Archives of General Psychiatry 38, 776–784.
Maxwell, A. E. (1971). Multivariate statistical methods and classification problems. British Journal of Psychiatry 119, 121–127.
Maxwell, A. E. (1972). Difficulties in a dimensional description of symptomatology. British Journal of Psychiatry 121, 19–26.
Mortimer, A., Lund, C. & McKenna, P. (1990). The positive–negative dichotomy in schizophrenia. British Journal of Psychiatry 157, 41–49.
Peralta, V., De Leon, J. & Cuesta, M. (1992). Are there more than two syndromes in schizophrenia? A critique of the positive–negative dichotomy. British Journal of Psychiatry 161, 335–343.
Philips, L. (1953). Case history data and prognosis in schizophrenia. Journal of Nervous and Mental Diseases 117, 515–525.
Pogue-Geile, M. (1989). The prognostic significance of negative symptoms in schizophrenia. British Journal of Psychiatry 155 (suppl. 7), 123–127.
Pope, H. & Lipinski, J. (1978). Diagnosis in schizophrenia and manic depressive illness. Archives of General Psychiatry 35, 811–828.
Prentky, R., Lewine, R., Watt, N. & Fryer, J. (1980). A longitudinal study of psychiatric outcome: developmental variables vs. psychiatric symptoms. Schizophrenia Bulletin 6, 139–148.
Shepherd, M., Watt, D., Falloon, I. & Smeeton, N. (1989). The Natural History of Schizophrenia: a Five-year Follow-up Study of Outcome and Prediction in a Representative Sample of Schizophrenics. Psychological Medicine, Medicine, Monograph Suppl. 15. Cambridge University Press: Cambridge.
Soni, S., Hollis, S., Reed, P. & Musa, S. (1992). Syndromes of schizophrenia on factor analysis. British Journal of Psychiatry 161, 860–861.
Soskis, D. & Bowers, M. (1969). The schizophrenic experience: a follow-up study of attitude and post-hospital adjustment. Journal of Nervous and Mental Disease 149, 443–449.
Spitzer, R., Fleiss, J., Endicott, J. & Cohen, J. (1967). Mental status schedule. Archives of General Psychiatry 16, 479–493.
Spitzer, R., Gibbon, M. & Endicott, J. (1975). The Global Assessment Scale (GAS). New York State Psychiatric Institute: New York.
Spitzer, R., Endicott, J. & Robins, E. (1978). Research diagnostic criteria: rationale and reliability. Archives of General Psychiatry 35, 773–782.
STATA Corporation (1993). STATA Reference Manual: Release 3.1, 6th edn. College Station: TX.
Stephens, J. & Astrup, C. (1963). Prognosis in ‘process’ and ‘nonprocess’ schizophrenia. American Journal of Psychiatry 119, 945–953.
Strauss, J. S. & Carpenter, W. T. (1978). The prognosis of schizophrenia: rationale for a multidimensional concept. Schizophrenia Bulletin 4, 56–67.
Thompson, P. & Meltzer, H. (1993). Positive, negative, and disorganisation factors from the schedule for affective disorders and schizophrenia and the present state examination. British Journal of Psychiatry 163, 344–351.
Wechsler, D. (1955). Wechsler Adult Intelligence Scale: Manual. Psychological Corporation: New York.
Wing, J. K., Cooper, J. E. & Sartorius, N. (1974). The Measurement and Classification of Psychiatric Symptoms. Cambridge University Press: Cambridge.
World Health Organization (1992). WHO Coordinated Multi-center Study on the Course and Outcome of Schizophrenia. WHO: Geneva.