Nature and nurture in anorexia nervosa: A study of 34 pairs of twins, one pair of triplets, and an adoptive family

Abstract

This paper reports observations following on a study of anorexia nervosa in 34 twins and one set of triplets, and within which approximately half the monozygotic (MZ) twins displayed concordance, compared with 7% of the dizygotic (DZ) twins. One additional case, involving childhood adoptions, is described, wherein neither genetic nor specifically assortative selection factors seem to have been at work. The findings suggest that genetic and environmental factors can interact to contribute to the development of this apparently culture‐based and multifactorially derived condition. A number of possible genetic strands to the condition are proposed; probably not all of them are specifically necessary for its development. The same may apply to experiential influences. Elsewhere it has been argued that the one essential charactistic of anorexia nervosa is avoidance behavior and the factors permitting and facilitating it (Crisp, 1980). Experiential influences, in the form of psychological maturational challenges in adolescence impinging on constitutional propensities to the point of precipitating the disorder out, would seem often themselves to have been influenced by constitutional psychological characteristics and earlier childhood experiences. A further pooling and study of all known twin and adoptive cases might now advance our knowledge of this condition further.

Some possible approaches to prevention of eating and body weight/shape disorders, with particular reference to anorexia nervosa

“…Thus, there has probably been an epidemic of anorexia nervosa in the last few decades (though I have expressed reservations about this because I believe it has always been more common than has been widely recognized during some epochs), and there is probably now an epidemic of bulimia nervosa. Nevertheless, our recent joint studies of twins with the Genetics Unit at the Institute of Psychiatry indicate the possibility of a strong genetic influence (Holland, Hall, Murray, Russell, & Crisp, 1984;Crisp, Hall, & Holland, 1985), although the impact of concordance on shared uterine experiences, nutritional and otherwise, of being raised together during infancy and childhood and of the psychodynamics of being identical twins, have not been assessed. However, we have known for a long time that anorexia nervosa, as well as obesity, runs in families: 5% or more of siblings or parents of the probands who attend us will be afflicted or have been afflicted, obviously a much higher incidence than is the case within the general population.…”

Some possible approaches to prevention of eating and body weight/shape disorders, with particular reference to anorexia nervosa

“…Thus, there has probably been an epidemic of anorexia nervosa in the last few decades (though I have expressed reservations about this because I believe it has always been more common than has been widely recognized during some epochs), and there is probably now an epidemic of bulimia nervosa. Nevertheless, our recent joint studies of twins with the Genetics Unit at the Institute of Psychiatry indicate the possibility of a strong genetic influence (Holland, Hall, Murray, Russell, & Crisp, 1984;Crisp, Hall, & Holland, 1985), although the impact of concordance on shared uterine experiences, nutritional and otherwise, of being raised together during infancy and childhood and of the psychodynamics of being identical twins, have not been assessed. However, we have known for a long time that anorexia nervosa, as well as obesity, runs in families: 5% or more of siblings or parents of the probands who attend us will be afflicted or have been afflicted, obviously a much higher incidence than is the case within the general population.…”

Common Genetic and Environmental Contributions to Anxiety Sensitivity, Anxiety, and Cognitive Symptoms of Eating Disorders in Adolescence

“…However, longitudinal research is needed to further test this theoretical model. Finally, while the relative contribution of genetic versus environmental contributions to eating disorders and symptoms is generally stable across time and cohorts ( Crisp et al, 1985 ; Waszczuk et al, 2019 ; Yao et al, 2021 ), sociocultural changes may correspond to varying shared and nonshared environmental influences on eating disorder symptoms. Indeed, research demonstrates that environmental contributions to eating disorder symptoms change across early childhood to adolescence ( Klump et al, 2010 ; Waszczuk et al, 2019 ), conceivably, in part, due to changes in environment (e.g., spending less time with parents and more time with peers).…”

Anorexia nervosa and social class

“…The nature of the genetic basis of anorexia nervosa is unclear (Crisp, Hall, & Holland, 1985). There is little evidence that such factors are related to social class, although a high growth rate has been linked in the past.…”

Some possible approaches to prevention of eating and body weight/shape disorders, with particular reference to anorexia nervosa

“…Thus, there has probably been an epidemic of anorexia nervosa in the last few decades (though I have expressed reservations about this because I believe it has always been more common than has been widely recognized during some epochs), and there is probably now an epidemic of bulimia nervosa. Nevertheless, our recent joint studies of twins with the Genetics Unit at the Institute of Psychiatry indicate the possibility of a strong genetic influence (Holland, Hall, Murray, Russell, & Crisp, 1984;Crisp, Hall, & Holland, 1985), although the impact of concordance on shared uterine experiences, nutritional and otherwise, of being raised together during infancy and childhood and of the psychodynamics of being identical twins, have not been assessed. However, we have known for a long time that anorexia nervosa, as well as obesity, runs in families: 5% or more of siblings or parents of the probands who attend us will be afflicted or have been afflicted, obviously a much higher incidence than is the case within the general population.…”

Common Genetic and Environmental Contributions to Anxiety Sensitivity, Anxiety, and Cognitive Symptoms of Eating Disorders in Adolescence

“…However, longitudinal research is needed to further test this theoretical model. Finally, while the relative contribution of genetic versus environmental contributions to eating disorders and symptoms is generally stable across time and cohorts ( Crisp et al, 1985 ; Waszczuk et al, 2019 ; Yao et al, 2021 ), sociocultural changes may correspond to varying shared and nonshared environmental influences on eating disorder symptoms. Indeed, research demonstrates that environmental contributions to eating disorder symptoms change across early childhood to adolescence ( Klump et al, 2010 ; Waszczuk et al, 2019 ), conceivably, in part, due to changes in environment (e.g., spending less time with parents and more time with peers).…”

Anorexia nervosa and social class

“…The nature of the genetic basis of anorexia nervosa is unclear (Crisp, Hall, & Holland, 1985). There is little evidence that such factors are related to social class, although a high growth rate has been linked in the past.…”

Some possible approaches to prevention of eating and body weight/shape disorders, with particular reference to anorexia nervosa

“…Thus, there has probably been an epidemic of anorexia nervosa in the last few decades (though I have expressed reservations about this because I believe it has always been more common than has been widely recognized during some epochs), and there is probably now an epidemic of bulimia nervosa. Nevertheless, our recent joint studies of twins with the Genetics Unit at the Institute of Psychiatry indicate the possibility of a strong genetic influence (Holland, Hall, Murray, Russell, & Crisp, 1984;Crisp, Hall, & Holland, 1985), although the impact of concordance on shared uterine experiences, nutritional and otherwise, of being raised together during infancy and childhood and of the psychodynamics of being identical twins, have not been assessed. However, we have known for a long time that anorexia nervosa, as well as obesity, runs in families: 5% or more of siblings or parents of the probands who attend us will be afflicted or have been afflicted, obviously a much higher incidence than is the case within the general population.…”

Common Genetic and Environmental Contributions to Anxiety Sensitivity, Anxiety, and Cognitive Symptoms of Eating Disorders in Adolescence

“…However, longitudinal research is needed to further test this theoretical model. Finally, while the relative contribution of genetic versus environmental contributions to eating disorders and symptoms is generally stable across time and cohorts ( Crisp et al, 1985 ; Waszczuk et al, 2019 ; Yao et al, 2021 ), sociocultural changes may correspond to varying shared and nonshared environmental influences on eating disorder symptoms. Indeed, research demonstrates that environmental contributions to eating disorder symptoms change across early childhood to adolescence ( Klump et al, 2010 ; Waszczuk et al, 2019 ), conceivably, in part, due to changes in environment (e.g., spending less time with parents and more time with peers).…”

Anorexia nervosa and social class

“…The nature of the genetic basis of anorexia nervosa is unclear (Crisp, Hall, & Holland, 1985). There is little evidence that such factors are related to social class, although a high growth rate has been linked in the past.…”