Long-term trends of symptoms and disability in schizophrenia and related disorders

Relatively few studies describe the long-term course of schizophrenia in well-defined cohorts of patients assessed soon after the illness onset. The aim of this paper is to describe the overall trend of schizophrenia in a 16-year follow-up study of patients and to explore the predictive value of several variables measured at the time of inclusion in the study. The course of the disorder is described along both a 'clinical' and a 'social' dimension.

The sample of 60 patients with a recent onset of a non-affective psychosis was first assessed in 1978-1980 as part of the study, coordinated by the WHO, on Reduction and Assessment of Psychiatric Disability. Data from the last follow-up are used to rate the overall trends of psychotic symptoms and of social disability. Based on a subdivision of the follow-up period into three sub-periods, the trend for the patients is rated for each of the two dimensions as improvement, deterioration, and no change or fluctuating. The associations of these trends with several predictor variables (age at onset, gender, martial status, education level, family history of mental illness, type of illness onset, personality assets) are explored by cross-tabulation (with calculation of the relative risk) and by a logistic regression model.

The predominant pattern for psychotic symptoms is improvement (55% of the subjects), while the predominant pattern for social disability is deterioration (45% of the subjects). A trend of improvement of psychotic symptoms correlated significantly with a negative family history of severe psychiatric disorder and with an acute type of illness onset. Only the first variable entered the logistic regression model. A trend of improvement of social disability correlated significantly with gender, marital status, presence of personality assets, and type of illness onset. All of these predictors entered the logistic regression model, with the exception of marital status; age at onset also entered the logistic regression.

Psychotic symptoms and social disability are relatively autonomous descriptors of the course of schizophrenia. A speculative hypothesis is that symptom course is more closely related to innate factors, while social disability is contingent upon the acquired level of personal and social competence at the time of illness onset. Future studies are needed to assess the effects of psychiatric interventions that could ameliorate the long-term prognosis of social disability in patients with schizophrenia.