Anxiety and Reward Interaction and Prediction of Outcomes in Anorexia Nervosa

The objective of this study is to understand the effects of anxiety on reward responsiveness in adolescents with anorexia nervosa (AN), and how this interaction predicts behavioral outcome subsequent to intensive treatment. Investigators plan to test, for the first time, how acute activation of threat related emotional circuitry reciprocally alters reward circuit activity, and to what degree this modulation predicts post treatment relapse. The severity of AN, its resistance to intervention, potential for quick return of illness, risk for long-term chronicity, and premature death, are well appreciated. Various forms of intensive treatment may succeed in at least partial weight restoration, yet early relapse is unusually high. The appearance early in life of prodromal anxiety phenotypes in individuals who subsequently develop AN is well documented and nearly universal. Anxiety proneness in concert with rigid self-discipline may therefore be predisposing substrates for sudden morbid apprehension about weight gain, and may contribute to subsequent behaviors including vigilant scrutiny of body size and shape and inflexible cognitive patterns regarding food and eating. In parallel, persons with restricting-type AN typically exhibit unease and reticence when exposed to novel, high reward environments. Most studies have found low fun-seeking, low novelty seeking, and reduced reward responsiveness in those with AN. In line with these observations, functional magnetic resonance imaging (fMRI) studies demonstrate aberrant reward sensitivity and reward circuit activation. However the interaction of anxiety and reward circuits has never been interrogated. There is substantial evidence of distinct yet overlapping neural systems mediating approach/reward and avoidance/anxiety, which are integrated in balancing and switching between behaviors related to the predominant valence state. Thus investigators posit that high degrees of reactivity of cortico-limbic circuits underlying anxiety may contribute mechanistically and functionally to diminished initial responsiveness to reward stimuli. This may translate clinically to lower motivation to engage in outpatient treatment - in effect, a lower drive to change behaviors and thought patterns necessary for maintaining gains or improving, based on expectancy of benefits of future outcome. The dynamic interaction between reward and anxiety systems in AN, and how dysregulation of connectivity within and between these systems mediates behavioral outcomes, has not previously been tested. Investigators will investigate this interaction using sequential fMRI paradigms and novel integrated functional-by-structural connectivity in individuals who have completed standard treatment on an eating disorder unit. Investigators will then investigate how this neural circuitry may predict degree of relapse during the subsequent 6 months.