Schizophrenia is a heterogeneous disease. The symptoms, course and outcome vary widely among patients. Together with multiple etiologic factors and pathophysiologic mechanisms, the extreme heterogeneity of schizophrenia suggests that it is not one disease, but hundreds of diseases, explained experts at WCP 2022.
Schizophrenia is not one disease
"Schizophrenia is characterized by extreme heterogeneity", said Professor Rajiv Tandon, Kalamazoo, MI, "not only in symptoms among patients and within an individual patient over time, but also in course and outcomes".1
"At least five dimensions of symptoms including negative symptoms, positive symptoms, motor symptoms, mood symptoms, and cognitive deficits,2 are produced by different brain circuitries and respond differently to antipsychotics",1 explained Professor Tandon.
The extreme heterogeneity of schizophrenia1 suggests there are hundreds of schizophrenias
In addition, hundreds of genes and a variety of environmental risk factors confer risk for schizophrenia.1
"However, despite intense research over 50 years and the availability of powerful brain imaging and investigative tools, understanding about schizophrenia is limited",1,3 said Professor Tandon.
Schizophrenia is characterized by at least five dimensions of symptoms produced by different brain circuitries and responding differently to antipsychotics1,2
"The multiple etiologic factors for schizophrenia and pathophysiologic mechanisms together with the extreme heterogeneity of phenotype suggest that schizophrenia is not one disease, but instead there are hundreds of schizophrenias", concluded Professor Tandon.
Abandon or rescue the construct of schizophrenia?
Professor Wolfgang Gaebel, Düsseldorf, Germany, cautioned against abandoning the construct of schizophrenia for now, because there is no better alternative.2 "The construct does not need to be rescued", he said, "but needs to transition to data-driven construct(s)". Professor Gaebel outlined steps to achieve this including:
The current construct of schizophrenia needs to transition to data-driven construct(s)
- Implementing the International Classification of Diseases 11th Revision4 (ICD-11) globally and harmonizing with The Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition5 (DSM-5)2
- Keeping the concept and name “primary psychoses”2
- Involving people with lived experience2
New constructs should be developed including fluid neuromental constructs instead of subtypes2
WCP : World Congress of Psychiatry
MI : Michigan
ICD-11 : International Classification of Diseases 11th Revision
DSM-5 : Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition
BE-NOTPR-0263, approval date : 02.2023
