Heritability was high among 17,000 Swedish twin pairs
The evidence for a genetic link to an eating disorder is broad and deep, but it has focused largely on AN and BN. A recent study has begun to shed light on genetic factors in those with avoidant resistant food intake disorder, or ARFID (JAMA Psychiatry. 2022. doi:10:1001/jamapsychiatry. 2022.4612). Children with ARFID, who are often labeled as picky eaters, are disinterested in food and have certain sensory aversions or fears about choking or vomiting. ARFID is the most common eating disorder treated in children: between 5% and 14% of children in inpatient programs, and nearly 25% of those in outpatient programs have now been diagnosed with ARFID.
The Swedish study included nearly 17,000 twin pairs. Data were collected between the ages of 6 and 12 and showed that 2% of the participants had a presentation consistent with ARFID. The extent of the risk of ARFID attributable to genetic factors vs shared and nonshared environmental factors was then calculated.
Strong heritability found
The heritability of ARFID was quite high: 0.79. The authors note that this makes ARFID “among the most heritable of psychiatric disorders.” They also remarked that the use of a group of markers rather than using a more typical diagnostic method is a limitation, but the method used does seem strong, so this is likely a minor limitation at most.
These interesting results tell us more about ARFID and seem to underscore its distinction from other eating disorders. More research on risk factors for ARFID is needed and may help lead to development of further treatment.
