Euphoria in multiple sclerosis: an investigation of constructs and symptons

Abstract

In multiple sclerosis (MS), some patients are said to present with unawareness of deficit, and positive mood and optimism that is out of place or incongruous given the patient's circumstances. The history of these symptoms, collectively known as euphoria, however, is characterised by marked inconsistencies regarding a number of aspects of these symptoms. This research attempted to investigate both the constructs, and the symptoms themselves, with the aim of better defining and broadening our understanding of euphoria. Results revealed that a change in the definition of euphoria appears to have occurred since the concept was introduced by Cottrell and Wilson. Different operational definitions appear to be partly responsible for the very different incidence rates reported throughout the literature. Instead of the classical three types of euphoria identified by the classical authors, or the single type utilised in the contemporary literature, the current research revealed two types of euphoria in MS (viz. positivity and unawareness). Positivity appears to be a subjective mood/outlook experienced by the patient and not an outward façade projected by the euphoric individual, and was defined in fairly subtle terms. Unawareness appears to relate to a number of domains (including physical, cognitive and mood or behavioural deficits), and was measured via participant/informant discrepancies on self-report questionnaires. Both positivity and unawareness were represented on a continuum and appeared to have different demographic, disease and cognitive correlates. Positivity was significantly predicted by a medical history of conditions that can affect neuropsychological functioning. Unawareness of physical deficits was associated with a female gender, a younger age, a lower income, relapsing-remitting course, a current disease state of relapse or exacerbation, a shorter disease duration, but a greater disease severity in terms of physical disability. Severity of the disease and the cognitive composite representing cognitive functions sub-served by the orbitobasal frontal cortex were also significant individual predictors of unawareness of physical deficits. Visuospatial ability significantly predicted unawareness of cognitive deficits. No demographic, disease or cognitive correlates of unawareness of mood or behavioural deficits were identified. Finally, no indisputable single cause underlying the two types of euphoria in MS identified by this research was isolated by the exploratory investigations undertaken; however interesting preliminary findings that may tentatively implicate executive dysfunction as well as, possibly, immunological disease processes in the etiology of euphoria in MS were revealed. These results have broadened our understanding of euphoria in MS and may shape both the research and clinical work with euphoric patients going forward.