Jim van Os and the ‘salience dysregulation syndrome’.

Jim van Os has long been one of my very favorite people in the world of psychosis. He is a professor of psychiatry at Maastricht, Netherlands and one of the truly innovative thinkers in the field.

Yesterday I came upon an editorial that he published this month (February 2009) in the British Journal of Psychiatry. In this concisely organized three-page article, van Os proposes a new diagnostic system for psychosis.

First he reminds the reader about the lack of validity of the current system, which is based on the construct of a disorder called ‘schizophrenia’. He reviews the evidence that this construct, on the one hand, lumps together people with widely different conditions and, on the other, separates people who have commonalities in terms of genetic and brain characteristics.

To replace the current diagnoses that are applied to people with psychosis, van Os proposed that everyone with psychosis (or sufficient severity to require psychiatric attention) be described as having a ‘salience dysregulation syndrome’. We have talked about salience in a previous posting of this blog. By adopting salience as a central construct van Os is using Kapur’s model in which psychosis (hallucinations and delusions) arise because the person has difficulty determining which of their mental experiences are relevant (and therefore need to be attended to and incorporated) and which are not. In Kapur’s model psychosis arises from an over inclusion of perceptions and experiences.

It is significant that van Os calls his construct a ‘syndrome’, rather than a ‘disorder’. He explains that a syndrome describes a set of signs and symptoms that tend to occur together but do not have a common cause (which would be the case for a true disorder).

A key point, as well, is that people with psychosis tend to experience other symptoms or have other characteristics. The hallucinations and delusions are, in fact, technically termed as ‘positive psychotic symptoms’ (positive meaning a symptom that is added to the usual human experience) to distinguish them from ‘negative symptoms’ (for example, an inability to experience pleasure or a lack of motivation). Disorganization tends to be present with psychosis and is included by some as a positive symptom, or seen as a separate dimension by others. As well, people with psychosis tend to have cognitive deficits in certain aspects of attention, memory and problem solving that appear to be present as part of development prior to the onset of psychosis. Depressive symptoms and manic symptoms also tend to co-occur with psychosis.

Using these six dimensions (positive symptoms, negative symptoms, disorganization, developmental cognitive deficits, depressive symptoms and manic symptoms), van Os constructs a diagram in which the severity of each symptom or deficit is rated for each individual person with psychosis. The ratings in all six dimensions provide a unique representation of the individual condition of each person.
The individual six dimension ratings provide, in the diagnostic system proposed by van Os, a way to divide the syndrome into three sub-categories.

The first category (salience dysregulation syndrome with developmental cognitive deficits) is used for people who have relative severe development cognitive deficits along with more severe negative symptoms and disorganization.

The second category (salience dysregulation syndrome with affective expression) is used for people who have relatively severe depressive and/or manic symptoms.

The third category (salience dysregulation syndrome ‘not otherwise specified’) is used for people who have relative severe positive psychotic symptoms and/or disorganization and relatively little in the way of cognitive deficits, negative symptoms or mood symptoms.

This new diagnostic system, that van Os is proposing, would encompass people who currently receive a diagnosis of schizophrenia or other ‘schizophrenia spectrum disorders’ and, as well, many who receive a diagnosis of bipolar disorder.

Whether this diagnostic proposal will ever be accepted and put into use in psychiatry certainly is not clear. It is timely in that both of the major diagnostic systems currently in use (DSM and ICD) are in the process of being revised. Dr. Van Os is, in fact, a member of the task force examining possible revisions to the DSM system in regard to psychosis.

However, there is a great deal of resistance to any major change in the diagnostic system for psychosis and the idea of putting aside the construct of schizophrenia, that has been so important to psychiatry for 100 years, is probably much too radical to be accepted.

Most people in psychiatry cling to the view that schizophrenia is a real disorder and forget that it is simply a construct used to try and bring order to the great range of mental conditions that include, as one of their features, the experience of psychosis.

Reference: Jim van Os (2009). A salience dysregulation syndrome. British Journal of Psychiatry 194, 101-103.