Abstract
M.Sc.
Anorexia Nervosa (AN) is a debilitating psychiatric illness characterised by a morbid fear of weight
gain and/or of eating, despite obvious emaciation. Poor understanding of the aetiology and
pathophysiology of AN has, however, hindered the development of effective interventions.
Nonetheless, over the past decade, neurocognitive endophenotypes have been increasingly
researched as promissory, clinically-relevant and heritable characteristics which might predispose
the development and persistence of AN, the elucidation of which might well lead to improved
treatment strategies. In particular, mental inflexibility, which can be measured on set-shifting (SS)
tasks, is frequently reported in subjects with AN, and is believed to reflect underlying subtle
dysfunction of corticostriatal brain circuitry. This study investigated whether SS difficulties were
present in a sample of South African anorectics. The Wisconsin Card Sorting Test (WCST) was used
to measure SS ability in 10 young women with current AN, and in 10 matched healthy controls (HC).
This study also measured eating-related psychopathology, Body Mass Index (BMI), and depressive,
anxiety, and obsessive-compulsive symptomatologies, and obtained as well an estimate of
intelligence, in case these factors might independently influence WCST performance. Contrary to
prediction, anorectics performed significantly better on the WCST than did individuals from the HC
group, making a smaller number of incorrect responses and proportionately fewer perseverative
errors. Controlling statistically for the aforementioned potentially-confounding variables did not
change these results. This is the first study to have shown superior SS performance in an AN group,
and suggests that SS might be intact, or adequately compensated for, in younger, less-severely
affected patients with a concomitantly shorter illness duration. Further studies, on larger samples of
similarly-aged anorectics, with less severe pathology and shorter illness duration, are necessary to
explore the generalizability and implications of this unexpected finding.