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Behavioural differences between twin and non‐twin female sibling pairs discordant for anorexia nervosa
Author(s) -
Waters Brent G. H.,
Beumont Pierre J. V.,
Touyz Stephen,
Kennedy Margaret
Publication year - 1990
Publication title -
international journal of eating disorders
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.785
H-Index - 138
eISSN - 1098-108X
pISSN - 0276-3478
DOI - 10.1002/1098-108x(199005)9:3<265::aid-eat2260090304>3.0.co;2-x
Subject(s) - anorexia nervosa , psychology , etiology , monozygotic twin , twin study , sibling , sister , daughter , developmental psychology , eating disorders , psychiatry , clinical psychology , genetics , heritability , evolutionary biology , sociology , anthropology , biology
Despite the voluminous literature on anorexia nervosa, its aetiology remains an issue of speculation and debate. Family influences have long been considered important, but genetic factors only recently have attracted interest. We surveyed a consecutive sample of anorexia nervosa patients referred to our service and identified 11 patients who were members of a same‐sex twin pair. To our surprise, in no instance was there evidence that the co‐twin was concordant for the illness. This finding contrasts with other reports in the literature, and it aroused our interest in the effects of being a twin on susceptibility to the illness. The aim of the present study was to determine whether there were any significant differences in premorbid factors and in symptoms following the development of the illness in 11 twin anorexia nervosa females who were compared with 11 non‐twin anorexic patients. The development of each patient was also contrasted with that of a sister. The development of each patient was elicited from the patient's mother by means of an interview schedule that contained questions relating to parental background, birth history, infancy, and adolescent development stages, as well as daughter's attitudes towards school, food, appearance, and weight‐reducing behaviours, including eating, exercise, and sport. The findings suggest that there may be differences in clinical pictures presented by twin and non‐twin anorexia nervosa patients that could influence response to treatment and outcome.