Genetic Basis of Anorexia: Twin Studies

Holland et al. (1988) carried out twin studies to show the influence of ______ and nurture on the development of anorexia.

MZ twins have a concordance rate of 56% for the development of anorexia, but DZ twins only have a 5% concordance rate, indicating a strong ______ influence.

Zeeland (2014) compared 152 genes in 1205 women with AN and 1948 without the condition and found that variants of the Ephx2 gene were more common in those with ______.

Ephx2 codes for an enzyme involved in the metabolism of ______, which is significant as individuals with severe symptoms of anorexia have abnormally high levels of cholesterol.

Imbalances of the neurotransmitters dopamine and serotonin may cause anorexia. High levels of serotonin suppress appetite and increase anxiety and obsessive behaviour, which are characteristics of ______.

Bailer et al. suggested that anorexia may have a neural basis, with high levels of serotonin suppressing appetite and increasing anxiety and obsessive behaviour, typical of individuals with ______.

Increased serotonin activity in women recovering from restrictive type anorexia or binge eating was associated with higher levels of ______

Persistent disruption of serotonin levels may lead to increased ______, which could trigger AN

Kaye et al. (1991) used a PET scan to compare dopamine activity in the brains of 10 women recovering from anorexia and 12 healthy women, finding overactivity in the dopamine receptors of the women with AN in the ______ where dopamine plays a part in the interpretation of harm and pleasure

Individuals with anorexia find it difficult to associate good feelings with things such as ______, which people find pleasurable

Kaye et al. (1999) compared women diagnosed with anorexia and women who had no history of eating disorders, finding that the HVA levels of the women with anorexia were 30% lower than for the non-AN women, on average. These findings strongly suggest that a disturbance of ______ metabolism may contribute to the symptoms of anorexia

Nunn et al. (2012) argued that serotonin on its own does not distinguish between people who have AN and those who do not. AN is better explained by considering the interaction between serotonin and another neurotransmitter- ______