CLINICAL HANDBOOK OF SCHIZOPHRENIA

104 I. CORE SCIENCE AND BACKGROUND INFORMATIONcourse of different dimensions of the illness. Prolonged DUP (maximum of psychoticsymptoms) has been found to predict psychotic symptoms but not negative symptoms. Incontrast, prolonged DUI (maximum of negative symptoms) has been found to predictmore negative symptoms, social impairment, and downward social drift. The finding thatduration of each symptom dimension significantly predicts the severity of that samesymptom dimension is in line with the relative independence of the positive and negativesymptoms in the long-term course of schizophrenia.After it became clear that functional impairment and the bulk of the social consequencesfrequently emerge before first therapeutic contact, interest grew in delaying psychosisonset or ameliorating the illness by early recognition and early intervention. Thereis evidence that cognitive-behavioral therapy in combination with low doses of antipsychoticmedication significantly reduce transition to psychosis within 1 year in compliant,high-risk patients compared to controls. But it is not yet clear whether transitions to psychosisare merely postponed, or whether the effect is permanent that also leads to a bettercourse and social outcome of schizophrenia in the long term.An explanation of the association between DUP and an unfavorable illness course asa result of a neurotoxic effect of psychosis has to consider the possibility that the effectmight be confounded by preceding disease-inherent factors. A highly acute onset withoutmore severe negative symptoms is generally associated with a good functional and socialprognosis, whereas an insidious, lengthy onset, with a high frequency of negative symptomsand severe cognitive impairment, predicts a poor outcome.DESCRIPTIVE ASSESSMENT AND CLASSIFICATIONOF TYPES OR TRAJECTORIES OF ILLNESS COURSEMany studies of the course of schizophrenia before 1990 were based on patients whosehistories of illness duration already differed considerably at the time of inclusion in thestudies. As a result, unfavorable courses were overrepresented in these samples. Not untilrecently have a growing number of large-scale follow-up studies starting in the first psychoticepisode been published.Because representative population samples of first-episode probands are difficult to recruit,most follow-up studies proceed from first admissions to a particular service or hospital.Depending on the clients served by the particular services, this approach may lead to distortedsamples. For example, due to an overrepresentation of young black males in publicmental hospitals, most of the older follow-up studies in the United States arrived at higherincidence rates for young men and a less favorable course compared to women. Recent studiesshow that only young males fall ill with schizophrenia more frequently and more severelythan do premenopausal women. Postmenopausal women show higher incidence rates andfrequently more severe illness courses than their male counterparts. One possible reason isthat women at this age lose the protective effect of estrogen.Kraepelin attempted to reduce the multitude of trajectories representing descriptivetypes of illness course. All constructs proposed so far are unsatisfactory, as demonstratedby the comparison of proportions of cases and different types of course from five longtermstudies of schizophrenia (Figure 11.1). This lack of concordance with hypothesizedtrajectory types reflects the high degree of interindividual variability in the course ofschizophrenia.The only sensible and practical solution at present is to distinguish a few typical trajectorieson the basis of a limited number of parameters, as done by Shepherd, Watt, Falloon,and Smeeton (1989) in their four types based on two parameters (number of episodes withpsychotic symptoms and amount of functional impairment) measured over time.