Jamie Murphy

Where is the border of sanity in psychosis?

Evidence that variation in the psychosis phenotype can be better represented by the concept of a continuum stems from decades of research indicating that schizotypal traits are commonly identifiable in ‘healthy’ individuals, and by more recent discoveries indicating that large numbers of the population report psychotic-like experiences (PLEs) without seeking psychiatric treatment; although they may seek help in other ways. Evidence has also shown that those who experience PLEs are often at higher risk of transitioning to psychotic disorder. While subclinical psychotic experiences are transitory in about 80% of individuals, around 20% go on to develop persistent psychotic experiences and 7% go on to develop a psychotic disorder. In most cases however it seems that PLEs are not associated with distress, and do not lead to a malign outcome. Some therefore have argued that subclinical or psychotic-like experiences in the general population must be distinct from ‘true’ symptoms of psychosis, as they are often too mild and transient to be clinically meaningful, and are not specific to disorder (e.g. schizophrenia).

As a consequence researchers worldwide have begun to employ and exploit a range of sophisticated analytic techniques in an attempt to explore the boundaries of psychosis. The resulting models have begun to challenge and change our understanding of the context, expression and course of psychosis, and our long held preconceptions about its status as a distinct, dichotomous, disease construct.

In this lecture, a series of sophisticated models, tested on data from a variety of European and American general population epidemiological surveys, will be presented. The findings will show (i) that ‘living with psychosis’ may apply to many more people than we might think (ii) that subclinical psychosis is often clinically meaningful, (iii) that non-distressing PLEs may meaningfully inform distressing PLEs and (iv) how clinically defined psychosis often means psychosis in a context of trauma, threat, adversity, isolation and deprivation.