What is the correlation between saliva levels of dexamphetamine

Abstract

ABSTRACT Degree Project, Programme in Medicine 2017. Author: Sofia Henriksson. Institution: Pharmacology, Pharmacy & Anaesthesiology Unit, University of Western Australia, Perth. Title: “What is the correlation between saliva levels of dexamphetamine and performance on visual and auditory-visual illusions?” Background: Schizophrenia is a psychiatric disorder associated with dopamine (DA) hyperactivity. Given that dexamphetamine (DEX) elevates levels of DA in the brain, DEX challenges can be used to model schizophrenia in research. Hallucinations and delusions are two characteristic symptoms of schizophrenia and psychosis. Previous research suggests a widened temporal binding window in which sensory stimuli can bind to form one perception as a mechanism of how DA gives rise to hallucinations and delusions. Using illusion tests, sensory stimuli can be manipulated and perception measured in an objective manner. Looking into temporal and spatial windows in the visual-visual and visual-auditory sensory modalities, 26 healthy participants tested the Three Flash Illusion test (3-FI), Sound Induced Flash Illusion test (SIFI), Visually Induced Flash Illusion test (VIFI), Phantom Word Illusion (PWI) and McGurk effect on one day given DEX and one day given placebo. Aims: To determine levels of DEX in saliva samples taken during the testing days and correlate those levels closest in time to the illusion tests with performance on illusion test. Methods: Liquid-liquid extraction and high performance liquid chromatography was used to determine the levels of DEX in saliva. Raw data was analysed primarily with principal components analysis. Results: For those significant differences in performance on illusion tests between DEX and placebo days, levels of DEX in saliva correlated positively only with performance on VIFI and PWI tests and not in the McGurk illusion. Conclusions: DEX-levels in saliva showed in our study to be an unreliable predictor of performance on the illusion tests. However, more studies with greater sample sizes are necessary to draw any final conclusions.