As is evidenced by this special supplement of the British Journal of Psychiatry, negative symptoms have become the focus of an increasing research effort. We have recently reviewed this overall body of research in an attempt to understand its current status and to suggest directions for future work from a broad perspective (Pogue-Geile & Zubin, 1988). In contrast, the aim of this paper is to review concisely one specific aspect of this research — namely the prognostic and longitudinal characteristics of negative symptoms. Research findings on this general topic will be reviewed by addressing a series of more specific subquestions, which are outlined below. Throughout, the potential importance of when in the course of the disorder (i.e. during an acute episode or afterward) negative symptoms are assessed will be emphasised (Kay et al, 1986b).

Our reintroduction of the concept of negative symptoms in schizophrenia (Strauss et al, 1974) has been followed by much productive research on this topic. As in the work of Andreason, Crowe, and others, the focus of most of this research has been on improving descriptive assessments of these symptoms (Andreason, 1982) and exploring their biological correlates (Crowe, 1981). This work has been extremely important, but psychological and social aspects of negative symptoms are also important (Barton, 1959; Wing & Brown, 1970; Gruenberg, 1967), and in these areas there has been little research. Nevertheless, it is crucial to explore possible psychological and social factors in negative symptoms in order to understand the symptoms more fully and to provide a basis for more adequate prevention and treatment. It is also important to clarify psychological and social factors in these symptoms to provide a basis for more effective biological research, since the heterogeneity of negative symptoms at a psychological level could hide significant biological correlates.