The staging model in schizophrenia, and its clinical implications

Illnesses which develop in a complex way are best described in stages, and those stages will describe not only a particular point in the course of the disease but also the appropriate treatment for that stage. This approach has, over the years, proved to be very appropriate for planning the treatment of various cancers. It is suggested that in the same way, it can be very important in planning the treatment of a complex illness such as schizophrenia. We aim to describe the staging model of schizophrenia, show the neuroimaging and clinical evidence for it, and discuss its implications for treatment.

We propose that the development of schizophrenia can be described in at least three stages; the prodrome, the first episode, and the chronic phase. In order to describe these stages, we will use data derived wherever possible from literature published in Europe, and we will compare this with data produced from other continents of the world, notably Australia. This is done by reference to and examination of the original published literature, in order that this evidence may be tested against criteria for evidence of a staging model which we propose.

There is much data, from clinical studies which show that schizophrenia develops over time and that its presentation can be described in at least three stages in the development of a schizophrenic illness; the prodrome, the first episode, and the long term chronic phase. It is also true that there is a pre-morbid phase before the prodrome, where it is possible to identify delays in such signs of early neurodevelopment as early paediatric milestones which may suggest an increased risk of schizophrenia in the future. This is mirrored in descriptions of the MRI findings, with loss of gray matter beginning in the prodrome, as well as in changes in cognition which develop as the illness develops over time.

It follows from this model that treatment is different in all these three stages, and that the expected outcome of treatment will be different in each of the various stages of the illness. In all the phases of the illness, evidence based psychological interventions, including psycho-education, cognitive therapy, family interventions, and other interventions to prevent relapse work together with medication in order to optimise treatment.

Consequently, any attempt to optimise treatment in schizophrenia must take into account the different stages of the illness, and target outcomes must be appropriate for these stages. The treatments, both pharmacological and psychological must be appropriate to the stage of the disease. The application of treatment protocols which are inappropriate to the stage of the disease may lead to sub-optimal outcomes, and even to iatrogenic harm.