A Connection Between Anorexia Nervosa and Autism Spectrum Disorders?

Some common ground is found
between the two.

Recent investigations are exploring possible links between anorexia nervosa (AN) and autism spectrum disorders (ASDs). As Dr. Janet Treasure and colleagues noted, many investigators over the years have attempted to describe AN as a variant of other disorders, ranging from primary pituitary disorder to schizophrenia. One notable comparison has been made more recently between AN and ASDs.

ASDs are developmental disorders marked by abnormal social functioning, difficulties with communication, and repetitive behaviors. An overlap between patients with AN and those with ASDs was initially proposed on the basis of clinical and behavioral observations. Eating disturbances such as refusal to eat certain foods, sensitivity to texture or types of foods, and unusual behaviors at mealtimes are commonly noted in persons with ASD. In addition, teenage girls with a diagnosis of ASD are at greater risk of experiencing eating disorder symptoms than are their healthy peers, and 27% of girls with ASD report symptoms that fall within the eating disorders realm. Males with ASD are also are increase risk for low body weight and abnormal eating practices.

Dr. Treasure and colleagues at King’s College, London, recruited 40 adult AN patients (38 females, 2 males) from an outpatient eating disorder unit (Eur Eat Disord Rev 2011; 19;462). Participants were required to have a body mass index (BMI, or kg/m² below 18.5, and to be categorized by a trained eating disorder specialist according to the DSM-IV criteria for restrictive (n=12) or binge-purge (n=9) AN subtype of eating disorder not otherwise specified, AN type (EDNOS; n=19).

The AN patients were tested and compared against published ASD scores on Reading the Mind in the Eyes, Voice, and Films tasks (a measure that assesses empathy), the Wisconsin Card Sorting Task (WCST, a measure that assesses executive function), and the Embedded Figures Task (a measure that assesses detail focus, an aspect of central coherence).

Autism and AN shared some common features

The researchers found striking similarities between the AN patients and ASD samples on their test performances. According to the authors, the cognitive profile in current AN resembles that of ASD, with important clinical implications. Programs to improve social skills among persons with ASD have had some success and might be adapted to patients with AN. They also suggest that cognitive remediation therapies to improve difficulties with set-shifting and reduce bias toward detail may benefit patients with AN. Other areas for future research are examining possible shared endophenotypes in both groups and whether this improves with refeeding and weight restoration.

A second study: A subgroup identified

In a community-based longitudinal study, Dr. H. Anckarsäter and colleagues at the University of Gothenburg, Sweden, have identified a subgroup of patients with AN who meet the criteria for ASD (Psychol Med 2010; Dec 20:1-11 [Epub ahead of print]). These patients have sociocommunicative problems corresponding to those reported in persons with ASDs. The researchers compared clinical problems, personality traits, cognitive test results and outcomes among 16 subjects with teenage-onset AN and matched controls from a longitudinal Swedish study including four waves of independent assessments from the teens to the early 30s. The fourth wave included the Structured Clinical Interview for DSM-IV (SCID I and SCID II), interviews, the Asperger Syndrome Diagnostic Interview, self-assessments by the Autism Spectrum Quotient and the Temperament and Character Inventory, neurochemical tests, and other tests.

The Swedish researchers found that the AN + ASD group had the highest prevalence of personality disorders and the lowest Morgan-Russell scores. (This test assesss eating disorder status and lower scores signify more eating disorder pathology.)The non-ASD-AN group also differed significantly from ASD controls on personality traits related to poor interpersonal functioning and on neurocognitive tests.