Reward System Abnormalities in Anorexia Nervosa

Abstract

Anorexia nervosa (AN) is associated with the highest mortality rate of any psychiatric illness 1 as well as significant health care costs and lost wages. While there have been notable advances in understanding biobehavioral mechanisms of AN, the brain systems that underlie the illness remain poorly understood. Clinically, it is widely accepted that the critical first step in treatment is renourishment-that is, restoring individuals to a healthy body weight. Yet knowing that the primary medical intervention is simply to eat does not, in itself, change behavior. In fact, even after full weight restoration, individuals with AN continue to restrict caloric and fat intake, which is associated with poor longer-term outcomes. 2 The severity and persistence of this illness makes understanding the pathophysiology and neural mechanisms of AN a research priority.In a bottom-up approach to identifying brain mechanisms of illness, neural systems that have been well characterized in healthy individuals are probed to test hypotheses about abnormalities in psychiatric illness. In this issue of JAMA Psychiatry, Frank et al 3 present the most recent findings from programmatic research examining reward and related neural systems in AN. Their model hypothesizes that the dopamine system is affected by AN-induced starvation. They propose that this is reflected in heightened prediction error response, a neural activation pattern associated with dopamine and thought to be a critical learning signal in the brain, 4 and that stress and high anxiety influence prediction error to perpetuate illness. This kind of integrative model of complex illness with programmatic testing of neurobiological hypotheses is an aspiration in the field of eating disorders. The work draws together ideas about harm avoidance traits, high cortisol levels, and abnormal neural responses to taste, which have been examined to some extent in prior work. 5 Furthermore, this study includes data from 56 adolescents and young adults with AN, 3 a sample size much larger than most studies in this field.In the study task, participants were presented with a stimulus and learned which images would be followed by receipt of a sweet taste. The associations become probabilistic, and on some trials, the predictions were violated and sweet liquid was delivered in response to the wrong stimulus or not delivered when it was expected. 3 Prediction error occurred when the sweet taste was either omitted or was received unexpectedly. Functional magnetic resonance imaging measures the blood oxygen leveldependent signal response in areas known to reflect the dopamine prediction error signal, such as the striatum. The ingestion of sweet taste as an outcome is presented as having relevance in

The predictive value of the early maladaptive schemas in social situations in anorexia nervosa

“…In line with previous literature findings, our AN patients presented a lower mood baseline and a higher EMSs score compared with HCs (Damiano et al, ; Meehan, Loeb, Roberto, & Attia, ). This is consistent with previous literature that showed how AN patients present a specific temperamental, cognitive, and behavioural profile with a rigid approach to changes that can affect a mild, flexible mind state as well as their connection with feelings and emotions (Duffy et al, ; Kaye et al, ; Oldershaw, Startup, & Lavender, ; Steinglass & Foerde, ). The literature has already shown that the AN patients present lower self‐esteem, higher fear of negative evaluation, and higher social physical comparison than controls, which are feelings that can affect social relationships (Cardi et al, ; Duarte, Ferreira, & Pinto‐Gouveia, ).…”

Altered Medial Frontal Feedback Learning Signals in Anorexia Nervosa

“…Although the model 245 did not uncover a group difference in a feedback sensitivity parameter, the finding that patients 246 tended to base their decisions on recent experience is commensurate with our finding of increased 247 learning rate in AN. The current evidence of altered decision-making in response to negative 248 feedback is in line with notion of altered reinforcement learning in AN (1)(2)(3)(4)(5)8) and, considered in 249 light of similar recent findings (13), is suggestive of a particular sensitivity to punishment. Decision-250 making may be intact, however, in paradigms that don't include negative feedback, at least in 251 adolescents (19,59).…”

Neural Insensitivity to the Effects of Hunger in Women Remitted From Anorexia Nervosa

“…We only included participants who were weight stable (<3 kg weight change) and physiologically and cognitively remitted from AN for at least one year, and we systematically monitored and manipulated pre-scan nutritional status. In terms of limitations, the passive task was designed specifically to characterize differences in hard-wired circuitry underlying neural sensitivity to gustatory processing, limiting our ability to assess top-down cognitive control, decision-making, or learning 46 . Unexpectedly, all participants rated the water as more pleasant-tasting than the sucrose solution and both the water and sucrose solutions as moderately pleasant-tasting.…”