Psychologists investigate cognitive failings of eating disorder sufferers

Sufferers of eating disorders have problems with certain mental tasks; this is the finding of a comprehensive overview of studies examining the link between cognitive deficits and eating disorders, published online in the Journal of Neuropsychology today, 22nd July 2009.

Professor Konstantine Zakzanis from the University of Toronto carried out an analysis of 27 studies that investigated the thinking of 608 anorexia nervosa sufferers, and 14 studies of 347 bulimia nervosa patients to look for consistent patterns in cognitive deficits.

Professor Zakzanis said: "Over the last 30 years, many psychological studies have tested people with anorexia or bulimia on tasks such as decision making, verbal memory and reaction times and have found that people with eating disorders perform worse than people who don’t have an eating disorder.

"In this overview we found consistent results that people with anorexia and bulimia have significant problems with some cognitive processes, and as sufferers’ body mass decreased, the severity of their cognitive impairments increased."

Anorexia sufferers were found to have particular impairments in spatial perception and representation, which could explain the distorted assessment of body image in patients with anorexia nervosa. Bulimia patients had less significant impairments than anorexia sufferers overall, but a particular impairment in impulsivity was observed, with 21 per cent of patients scoring worse on measures of impulsivity when compared to people without an eating disorder.

"These results tell us that people with eating disorders have particular patterns of cognitive deficits. However, at this stage we do not know whether these deficits are a result of abnormal eating patterns, malnutrition for example, or whether these cognitive deficits result in, or affect the progression of eating disorders," Professor Zakzanis continued. "If cognitive deficits are behind eating disorders this could help us to understand why certain people are affected and could help us to develop future psychological treatments."

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