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
The extreme heterogeneity of schizophrenia1 suggests there are hundreds of schizophrenias
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.
In addition, hundreds of genes and a variety of environmental risk factors confer risk for schizophrenia.1
Schizophrenia is characterized by at least five dimensions of symptoms produced by different brain circuitries and responding differently to antipsychotics1,2
However, despite intense research over 50 years and the availability of powerful brain imaging and investigative tools, understanding about schizophrenia is limited,1,4 said Professor Tandon. There is no diagnostic test or necessary or sufficient etiology or pathology for diagnosis.3
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.
Hundreds of genes and many environmental risk factors confer risk for schizophrenia1
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 Revision5 (ICD-11) globally and harmonizing with The Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition6 (DSM-5)
- Keeping the concept and name “primary psychoses”
- Involving people with lived experience
New constructs should be developed including fluid neuromental constructs instead of subtypes
- Dialogue with industry on selective treatments, e.g., for positive and negative symptoms
- Intensifying global research collaborations using an innovative, data-driven, bio-psychosocial, multi-level approach and encouraging the development of new constructs including fluid neuromental constructs instead of subtypes