Biomarker Symptom Profiles for Schizophrenia and Schizoaffective Psychosis

Abstract

Background: Neuroscience can assist clinical understanding and therapy by finding neurobiologi-cal markers for mental illness symptoms. Objectives: To quantify biomarkers for schizophrenia and schizoaffective disorder and relate these to discrete symptoms of psychosis. Methods: Within a case-control design with multiple exclusion criteria to exclude organic causes and confounding variables, 67 DSM IV-R diagnosed and 67 control participants from a defined hospital, clinic and community catchment area were investigated for candidate markers. Participants underwent protocol-based diagnostic-checking and symptom rating via Brief Psychiatric Rating Scale and Positive and Negative Syndrome Scale, functional-rating scales, biological sample-collection and sensory-processing assessment. Blood and urine samples were analysed for monoamine neuro-transmitters, their metabolites, vitamin cofactors and intermediate-substances related to oxida-tive stress and metabolism of monoamines. Neurocognitive assessment of visual and auditory processing was conducted at both peripheral and central levels. Biomarkers were defined by Re-ceiver Operating Curve (ROC) analysis. Spearman's analysis explored correlations between dis-crete symptoms and the biomarkers. Results: Receiver Operating Curve (ROC) analysis identified twenty-one biomarkers: elevated urinary dopamine, noradrenaline, adrenaline and hydroxy pyr-roline-2-one as a marker of oxidative stress. Other biomarkers were deficits in vitamins D, B6 and folate, elevation of serum B12 and free serum copper to zinc ratio, along with deficits in dichotic listening, distance vision, visual and auditory speed of processing, visual and auditory working memory and six middle ear acoustic reflex parameters. Discrete symptoms such as delusions, hos-tility, suicidality and auditory hallucinations were biomarker-defined and symptom biomarker correlations assumed an understandable pattern in terms of the catecholamines and their rela-tionship to biochemistry, brain function and disconnectivity. Conclusions: In the absence of a full diagnosis, biomarker-symptom-signatures inform psychiatry about the structure of psychosis and provide an understandable pattern that points in the direction of a new neurobiological system of S. Fryar-Williams, J. E. Strobel 79 symptom-formation and treatment.