Stability trends and longitudinal correlations of negative and positive syndromes within a three-year follow-up of initially hospitalized schizophrenics.

Our study investigates whether the distinction between positive and negative symptoms in schizophrenia--as discussed in the literature--can be confirmed by a factor analysis and whether such a distinction proves stability over time. In a further step, symptom factors are correlated to different external variables for the purpose of validation. Processed data cover 36 months obtained from a prospective 5-year follow-up study of 163 initially hospitalized schizophrenics. The results permit for dividing the symptoms into a total of five factors--two representing positive and negative symptoms and one representing the general neurotic syndrome. This factor structure proved to be stable over time. Correlations between symptom factors and external variables justify a trait-interpretation of the negative factor anhedonia.