Comorbidity between eating disorders and anxiety disorders: a review

Pathologic fear conditioning and anorexia nervosa: on the search for novel paradigms

Although eating disorders have been the focus of an unprecedented explosion of clinical interest in recent years, the etiology of anorexia nervosa remains elusive. It is hypothesized that an underlying causative mechanism involves a propensity to extreme fear conditioning and greater than normal resistance to its extinction. Knowledge accrued from recent behavioral, genetic, and neuroanatomic research on anxiety may yield further insight into the pathogenesis of anorexia nervosa, which can be subjected to experimental validation using objective measures of classical fear conditioning and functional neuroimaging of brain structures mediating fear behavior.

Comparison of 35% carbon dioxide reactivity between panic disorder and eating disorder

Patients with panic disorder (PD) are hyperreactive to carbon dioxide (CO(2)), but the specificity of this characteristic to PD is controversial. Anxiety and phobic symptomatology are common to both panic and eating disorders (ED). To investigate the specificity of CO(2) hyperreactivity to PD, the responses to inhalation of a 35% CO(2) and 65% oxygen (O(2)) gas mixture were assessed. Reactions to 35% CO(2) challenge were compared among three groups of age- and sex-matched subjects: 14 patients with ED, 14 patients with PD, and 14 healthy controls (HC). A double-blind, randomized, crossover design was used. Only patients with PD showed a strong reaction to 35% CO(2), while patients with ED and HC did not react significantly. The results support the specificity of CO(2) hyperreactivity to PD.

Refinement of behavioural traits in animals for the genetic dissection of eating disorders

Both twin and family studies have revealed the involvement of genetic factors in disorders that affect the regulation of body weight, such as obesity and anorexia nervosa. However, pinpointing the genes that contribute to these human disorders has not yet been very successful. In contrast, genetic studies in animals have been basic for the identification of many genes involved in the regulation of various physiological processes of energy metabolism. We thus plan to review here ways in which findings from animal studies and what is known about behavioural diversity in the human population with eating disorders can be combined. This would probably optimise phenotype-based candidate gene analysis in humans.

Anxiety disorders in subjects seeking treatment for eating disorders: a DSM-IV controlled study

Women who were referred with an eating disorder (ED) were compared with a matched normal control group to answer the following questions: What are the frequencies of anxiety disorders in cases of anorexia and bulimia nervosa diagnosed according to DSM-IV criteria? Are anxiety disorders significantly more frequent among women with an eating disorder than among women from the community? We assessed the frequencies of six specific anxiety disorders among 271 women with a current diagnosis of anorexia or bulimia nervosa and 271 controls, using the Mini-International Neuropsychiatric Interview, French DSM-IV version. A lifetime comorbidity with at least one anxiety disorder was found in 71% of both the anorexic and the bulimic subjects, significantly higher than the percentage of controls with an anxiety disorder. The prevalence was significantly higher in the eating disorder groups than in controls for most types of anxiety disorder, and between 41.8 and 53.3% of comorbid cases had an anxiety disorder preceding the onset of the eating disorder. Anxiety disorders are significantly more frequent in subjects with eating disorders than in volunteers from the community, a finding that has important etiological and therapeutic implications.