Central coherence in eating disorders: a systematic review.

C. Lopez1*, K. Tchanturia1, D. Stahl2 and J. Treasure3

1 Division of Psychological Medicine, Eating Disorders Research Unit, Institute of Psychiatry, King’s College London, London, UK

2 Department of Biostatistics and Computing, Institute of Psychiatry, King’s College London, London, UK

3 Eating Disorders Research Unit, Department of Academic Psychiatry, King’s College London, London, UK

Background. This review systematically appraised the research evidence for local versus global information processing to test the hypothesis that people with eating disorders (ED) had weak central coherence.

Method. Searches on Medline, EMBASE, PsycINFO and ISI Web of Science databases were conducted in November 2006 and subsequently updated in September 2007. Each search was conducted in two steps: (1) neuropsychological tasks measuring central coherence and (2) words related to cognitive functioning in eating disorders. Data were summarized in a meta-analysis if the number of studies for a given test was >5.

Results. Data were extracted from 16 studies. Meta-analyses were conducted for four tasks obtaining moderate effect sizes. The majority of studies found global processing difficulties across the ED spectrum. The results are less clear regarding local processing.

Conclusions. People with ED have difficulties in global processing. It is less certain as to whether they have superior local processing. Currently, there is insufficient evidence to refute the weak central coherence hypothesis.

Received 13 December 2007 ; Revised 17 March 2008 ; Accepted 31 March 2008 ; First published online 30 April 2008

Key words : Anorexia nervosa, bulimia nervosa, cognitive function, global processing, local processing, weak coherence.