Remission in schizophrenia: proposed criteria and rationale for consensus
Andreasen NC, Carpenter WT, Kane JM, Lasser RA, et al.;
Commented by , 22 Mar 2005
Aim of the study
Researchers in the field of schizophrenia have tried for a long-time to define "response" to treatment. Various definitions such as an at least 20% or 50% reduction of the initial score of the Brief Psychiatric Rating scale (BPRS) or the Positive and Negative Syndrome Scale (PANSS), or a Clinical Global Impressions Scale (CGI) of at least minimally or much improved have all been used.
However, there was no consensus as to which cut-off should be used in which situation. In addition, the meaning of all these cut-offs from a clinical perspective was unclear.
New advances in the understanding of the etiology, course, and treatment of schizophrenia have raised the expectations from a simple definition of "response" - basically meaning that the patient’s status has to some extent improved - to more rigorous criteria of "remission". Thus, the aim of the current proposal was to provide operational remission criteria for schizophrenia.
Methods
An expert working group was formed that reviewed available definitions and concepts of remission in schizophrenia and other psychiatric disorders such as depression. It turned out that in the field of schizophrenia the issue is more complexe than in mood-disorders, where simple cut-offs of scales such as a total score of the Hamilton Rating Scale of Depression below eight are widely accepted criteria.
The problem in the field of schizophrenia is that it is composed of a number of symptom domains such as positive symptoms, negative symptoms and cognitive dysfunction, the occurence of which can differ during the course of treatment.
Therefore, a novel approach had to be used that combined the core symptoms of schizophrenia as defined by DSM-IV with the PANSS items reflecting these symptoms.
Results
The new remission criteria can be defined using the PANSS or using combinations of items of the BPRS, of the Scale for the Assessment of Negative Symptoms (SANS) and of the Scale for the Assessment of Positive Symptoms (SAPS). Using the PANSSS is, however, the easiest way, because it covers all relevant symptoms.
The following passage explains which symptoms domains described by DSM-IV are covered by which items of the PANSS:
- Delusions – items P1 (delusions) and G9 (unusual thought content)
- Hallucinations – item P3 (hallucinatory behaviour)
- Disorganised speech – item P2 (conceptual disorganisation)
- Grossly disorganised or catatonic behaviour – item G5 (mannerism and posturing)
- Negative symptoms – items N1 (blunted affect), N4 (social withdrawal) and N6 (lack of spontaneity).
A patient needs to be scored "mildly ill" or better according to all of these items to fulfil the remission criteria.
As an additional time criteria a persistence of the remission criteria for at least 6 months is necessary. However, the symptom criteria can also be used without the duration criteria.
Discussion
The main contributions of this innovative approach for defining "remission" of schizophrenia is that it provides a greater clarity around treatment goals, that it should make the interpretation of trial results easier and that it can also enhance the comparability of research findings.
It can be a matter of debate as to whether the defnition was conservative enough to speak of remission, since minimal symptoms are still allowed. This probably reflects a certain compromise in the sense that even more rigorous criteria would be hard to achieve in a large number of patients.
Furthermore, according to the definitions of the PANSS such mild symptoms do not interfere with a person's functioning. The new criteria now need further examination of their validity and utility, as well as future refinement.