Reduced activation of brain networks underlying theory of mind is associated with treatment outcome in juvenile anorexia nervosa

Objective: Converging evidence suggests an impairment of social functioning in patients with anorexia nervosa (AN) which might be associated with long-term outcome. Recent behavioral studies have found deficits in theory of mind (ToM), the ability to understand the mental states of other people, in patients with AN. The present study aimed at elucidating the neural mechanisms underlying ToM-deficits in AN.

Method: 19 adolescent patients with AN and 21 age-matched controls were investigated using functional magnetic resonance imaging upon admission to hospital (T1) and at discharge from hospital after weight recovery (T2). We measured brain activation during a ToM-task that required the ability to attribute social intentions to videos of moving geometric shapes. In patients, clinical outcome was determined one year after admission (follow-up).

Results: Irrespective of the time point, AN patients showed reduced activation in middle and anterior temporal cortex and in the medial prefrontal cortex (mPFC) during the ToM condition. This hypoactivation could not be explained by starvation-induced changes in grey matter volumes. Hypoactivation in the mPFC at T1 was correlated with clinical outcome at follow-up.

Conclusions: Hypoactivation in the brain network supporting theory of mind may be associated with a social-cognitive endophenotype reflecting impairments of social functioning in anorexia nervosa. These dysfunctions may be predictive for a poor outcome at one year follow-up.