Behavioral Addictions _ _______________________________________________________________________
Binge eating disorder has a higher lifetime prevalence in the United States and worldwide than bulimia nervosa and anorexia nervosa combined [239]. Unlike bulimia nervosa and anorexia nervosa, binge eating disorder is relatively common in both sexes and across ethnic/racial minority groups, and is distributed across broader age groups [239]. As noted, binge eating disorder is significantly associated with elevated rates of medical and psychiatric comorbidity and impairment. It shares some features with, but is distinct from, the other eating disorders and obesity [243; 244; 245]. Binge eating disorder is typically first diagnosed during the early to mid-20s, with symptoms usually persisting well beyond mid-life. The disease course may crossover to and from buli- mia nervosa and anorexia nervosa. Binge eating disorder is associated with significant role impairment and relationship dissatisfaction. It is considered a significant public health prob- lem independently as well as for its association with chronic pain, other psychiatric disorders, obesity, and diabetes [246; 247; 248]. PATHOPHYSIOLOGY Evidence suggests that binge eating disorder overlaps with other behavioral and substance addictions. Persons with binge eating disorder show impairments across a range of compulsivity indi- ces comparable to those with alcohol use disorder [43; 249]. Binge-eating episodes may be triggered by a breakdown in self-regulation induced by sudden increases in negative affect and tension. Impairment in executive function is consistently found in eating disorders. With strong impulses or urges to eat, lack of inhibitory control may lead to impulsive eating and obesity in some [250]. In addition, dysregulation in dopamine, opioid, acetylcholine, and serotonin neurocircuitry in brain reward regions is implicated in the pathogenesis and mainte- nance of binge eating disorder [251]. There is growing interest in and debate about whether an addictive process contributes to problematic eating outcomes such as obesity. Craving is a core component of addiction but is little-studied in the context of addictive eating. In a commu- nity sample, overall food craving partially mediated the links between addictive eating and elevated body mass index (BMI) and binge-eating episodes. Cravings for sweets and carbohy- drates mediated the link between addictive eating and binge episodes. Cravings for fats mediated the link between addictive eating and elevated BMI. Craving was a key contributor to the link between addictive eating and pathologic outcomes [252]. Individuals with obesity vary in their experience of food cravings and reward-driven eating; both can be modulated by the neural reward system rather than physiologic hunger. In a trial that randomized women with obesity to naltrexone or placebo, a subgroup showed that addictive eating behavior and food-craving intensity was linked to reward-driven eat- ing, a trait-like index of three factors (loss of control over eating, lack of satiation, and preoccupation with food). In this
subgroup, opioidergic blockade with naltrexone reduced the positive association between reward-driven eating and craving intensity [253]. The stimulant lisdexamfetamine was approved for binge eating disorder treatment by the U.S. Food and Drug Administration (FDA) in 2015. Lisdexamfetamine consistently leads to weight decreases of 5.2% to 6.25%. Psychostimulants are known to facilitate response inhibition by modulating PFC function. Despite successful reduction or remission of binge eating with antidepressants or psychosocial treatment, significant weight loss in these patients has not been reported. Through modulation of prefrontal function, lisdexamfetamine may lead to additional improvements in inhibitory control that account for weight loss [251]. A systematic review of clinical and preclinical evidence for lisdexamfetamine efficacy found consistent evidence that the agent reduces food intake but limited evidence on its mechanism of action [254]. DIAGNOSIS The Yale Food Addiction Scale, based on DSM-IV criteria for substance dependence, was the first assessment tool for addic- tive eating behavior. Despite the “food addiction” naming, this scale assesses eating behavior and identifies eating patterns similar to behaviors in substance addiction [235]. Binge eating disorder was reclassified from a provisional diag- nosis in the DSM-IV to a formal eating disorder diagnosis in the DSM-5-TR ( Table 4 ) [11; 255; 256]. This disorder is characterized by recurrent episodes of binge eating, defined as eating patterns during discrete periods (i.e., two or more hours) that involve excessive, rapid food consumption. Other core features include a sense of lacking control over eating during binge episodes, significant psychological distress (e.g., shame, guilt) about binge eating, and the absence of recurrent compensatory behaviors (e.g., purging) [11]. A sense of loss of control during binge episodes is a core feature of binge eating disorder. The term “loss-of-control eating” is used to describe these episodes, but it is also used more broadly throughout the literature to describe binge-like eating behavior accompanied by a sense of loss of control that occurs across a wide spectrum of individuals. That spectrum includes, among others, individuals who exhibit some features of binge eating disorder but do not meet full diagnostic criteria for the disorder (i.e., subthreshold binge eating disorder) and individuals with other eating disorders [81]. The spectrum of loss-of-control eating also includes indi- viduals for whom meeting the diagnosis threshold of binge eating disorder is uniquely challenging, such as children and those who have undergone bariatric surgery. Bariatric surgery significantly reduces stomach size and capacity, rendering it physically impossible to meet the binge eating disorder criterion specifying that a larger than usual amount of food is ingested. In the bariatric surgery literature, loss-of-control eating is used to describe binge-like behavior that falls short of meeting this
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