Anorexia nervosa (AN) is an eating disorder characterized by a morbid fear of weight gain and a perception of being overweight despite objective evidence of weight loss and malnutrition. It has been estimated that almost 0.9% of women will suffer from AN at some point in their lives, and most cases of AN arise during adolescence. Even with appropriate treatment, only about half of patients with AN will have a full recovery, 30% partial recovery, and 20% will progress to having a chronic illness. Earlier, more aggressive treatment with appropriate nutritional recovery during adolescence offers the best chance of a full recovery. Treatment of AN is complicated by the high rate of comorbid psychiatric diagnoses, the physical and cognitive effects of the attendant malnutrition, and the lack of effective pharmacologic interventions. Approximately 75% of patients with AN have a comorbid psychiatric illness, including depression, obsessive compulsive disorder, and anxiety. Anxiety disorders in particular share attributes with AN, including perfectionism, rigidity, compulsivity, and harm avoidance in addition to trait anxiety. Complicating treatment, the risk and severity of patients' anxiety is enhanced by a lower body mass index (BMI), and this low BMI is the likely reason why standard medication treatments for generalized anxiety, such as selective serotonin reuptake inhibitors are ineffective. In order to address these treatment challenges, we propose to study the tolerability, feasibility and efficacy of a non-pharmacologic interventions for anxiety in adolescents with AN: omega-3 polyunsaturated fatty acid (PUFA) supplementation.

Over the past 15 years, there has been an interest in possible associations between fish oil and affective illness, particularly depression. Low plasma levels of docosahexaenoic acid, an essential fatty acid found in fish oil, are associated with low concentrations of cerebrospinal fluid 5-hydroxyindolacetic acid (5-HIAA), a marker of central nervous system serotonin turnover. Epidemiologically, those populations with higher fish oil consumption tend to have lower rates of depression, and reported low levels of fish consumption have been associated with a greater risk of depression in women. It has been hypothesized that omega-3 PUFAs alter brain phospholipid composition and enhance membrane fluidity, and this is supported by evidence that supplementation with omega-3 PUFAs decreases brain water proton transverse relaxation times in patients with bipolar disorder. The association with depression and the proposed mechanism of action elicited some interest regarding associations between omega-3 PUFAs and anxiety disorders. Supplementation trials have shown mixed results, with no effects for obsessive compulsive disorder in patients taking maximum doses of selective serotonin reuptake inhibitors, and another showing decreased anxiety symptoms in 22 patients enrolled in a substance abuse treatment program. Recently, Kiecolt-Glaser and colleagues described a decrease in test-related anxiety symptoms in a non-clinical sample of medical students related to supplementation with omega-3 PUFAs. Although there has been some interest in the use of omega-3 PUFA supplementation as an adjunctive treatment for anorexia nervosa, there have been no systematic trials.