The future of diagnosis in clinical neurosciences: Comparing multiple sclerosis and schizophrenia

Abstract

The ongoing developments of psychiatric classification systems have largely improved reliability of diagnosis, including that of schizophrenia. However, with an unknown pathophysiology and lacking biomarkers, its validity still remains low, requiring further advancements. Research has helped establish multiple sclerosis (MS) as the central nervous system (CNS) disorder with an established pathophysiology, defined biomarkers and therefore good validity and significantly improved treatment options. Before proposing next steps in research that aim to improve the diagnostic process of schizophrenia, it is imperative to recognize its clinical heterogeneity. Indeed, individuals with schizophrenia show high interindividual variability in terms of symptomatic manifestation, response to treatment, course of illness and functional outcomes. There is also a multiplicity of risk factors that contribute to the development of schizophrenia. Moreover, accumulating evidence indicates that several dimensions of psychopathology and risk factors cross current diagnostic categorizations. Schizophrenia shares a number of similarities with MS, which is a demyelinating disease of the CNS. These similarities appear in the context of age of onset, geographical distribution, involvement of immune-inflammatory processes, neurocognitive impairment and various trajectories of illness course. This article provides a critical appraisal of diagnostic process in schizophrenia, taking into consideration advancements that have been made in the diagnosis and management of MS. Based on the comparison between the two disorders, key directions for studies that aim to improve diagnostic process in schizophrenia are formulated. All of them converge on the necessity to deconstruct the psychosis spectrum and adopt dimensional approaches with deep phenotyping to refine current diagnostic boundaries.

Schizophrenia - Time to Commit to Policy Change

“…Heterogeneous proteomic results 115 and shared immune marker changes between schizophrenia, bipolar disorder and major depression 116,117 mean that multimodal approaches may still be required to accurately identify positive signals. 102,118,119 Regarding neuroimaging and electrophysiological biomarkers, consistent brain morphology changes in schizophrenia patients are apparent, 45,120,121 but…”

“…In terms of clinical presentation, there is no single test for schizophrenia and a diagnosis usually requires at least one assessment by a mental health specialist. Guidelines for diagnosing schizophrenia include confirming the presence of different aspects over time, which can include: [43][44][45] n Delusions. Ongoing progress in neuroscience research means that the list of potential outcomes that may be used to validate a diagnosis of schizophrenia in the future might include genetic, biological and chemical changes as well as cognitive assessments.…”

“…109 This approach has limited predictive value, particularly in the early disease stages. Today however relevant biomarkers for timely schizophrenia diagnosis are available: 109,45 n Neuroimaging: Used to reveal changes in the brain.…”

“…This approach should integrate large population-based research to understand neurobiological mechanisms, coupled with identification of biomarkers, blood examinations, functional brain imaging techniques, EEG for brain activity analysis, and polygenic risk scores for assessing genetic predispositions. 314 Although our understanding of psychotic disorders' neurobiology is advancing, 314 and biomarkers for schizophrenia are evolving, 109,45 there's still a pressing need for more research to pinpoint effective biomarkers. 314 Ensure early implementation of psychosocial therapies: Increase awareness of psychosocial therapies and promote use as a primary treatment approach.…”

Why is it so difficult to implement precision psychiatry into clinical care?

“…However, contrary to common belief, the diagnoses of mental disorders have good to very good reliability but only fair validity. 3 This means that based on clinical criteria such as ICD-11 or DSM-5, the replication of the diagnostic process by another clinician yields similar results. Compared to other medical disciplines like neurology, the reliability of the clinical diagnosis of multiple sclerosis (MS) is comparable to that of schizophrenia.…”