Monday, February 6, 2023

One Eating Disorder Found to Be More Heritable Than Others

Genetics play a strong role in the development of avoidant restrictive food intake disorder (ARFID), according to an analysis appearing in JAMA Psychiatry. The analysis suggests that ARFID is more heritable than other eating disorders.

“Unlike anorexia nervosa, dietary restriction in ARFID is not motivated by body image concerns or drive for thinness but rather based on sensory sensitivity to food qualities (e.g., texture, smell, taste), lack of interest in food/eating (ie, low appetite), and/or fear of aversive somatic consequences of food intake (e.g., choking, vomiting, allergic reactions), often in response to aversive eating experiences,” wrote Lisa Dinkler, Ph.D., of the Karolinska Institutet in Sweden and colleagues. “With an estimated prevalence of 1% to 5%, ARFID is at least as common as autism and potentially as common as attention-deficit/hyperactivity disorder (ADHD).”

Dinkler and colleagues used data from the Child and Adolescent Twin Study in Sweden, which aims to collect comprehensive psychiatric and developmental data on all twins born in Sweden since July 1, 1992.

The study population consisted of 33,902 children born between 1992 and 2010 (the twins were assessed at ages 9 or 12 depending on birth year). Overall, 682 children met the criteria for ARFID based on the DSM-5 definition of exhibiting avoidant/restrictive eating with clinically significant consequences that are not attributable to anorexia, bulimia, or a body image disturbance. The prevalence of ARFID was slightly higher in males (2.4%) than females (1.6%). Of this group, 67.2% experienced weight loss or failure to gain weight, 50.6% had problems with psychosocial functioning, 8.5% required supplements or tube feeding, and 0.6% had a nutritional deficiency.

Based on the prevalence of ARFID in identical and fraternal twins, Dinkler and colleagues estimated that ARFID risk was 79% due to heritable factors such as genetics or shared family environment. This rate was similar even after excluding children who had comorbid autism or another medical condition that could contribute to avoidant eating (for example, thyroid disorder). The 79% heritability is higher than what has been reported for anorexia (48% to 74%), bulimia (55% to 61%), and binge eating disorder (39% to 57%). The 79% heritability is on par with autism, schizophrenia, and ADHD, the authors noted.

“The high heritability of the ARFID phenotype provides strong support for future twin and molecular genetic studies of ARFID,” Dinkler and colleagues concluded.

To read more on this topic, see the Psychiatric News special report “Youth With Eating Disorders—Time Is of the Essence in Achieving Remission.”

(Image: iStock/cosmin4000)

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