Hypothesis: Clues From Mammalian Hibernation for Treating Patients With Anorexia Nervosa

Similarities and differences regarding acute anorexia nervosa and semi-starvation: does behavioral thermoregulation play a central role?

Objective

To clarify the association between acute anorexia nervosa (AN) and semi-starvation (SS) by focusing on similarities and differences in physiology, mood, and behavior.

Method

A comparison of published literature between these two groups.

Results

Both groups show similar hormonal and metabolic changes in response to caloric restriction and extreme weight loss (~25%). Associated changes result in a reduced body temperature (Tcore-low). Maintenance of body temperature within a specific range is crucial to survival. However, both groups cannot activate autonomic strategies to maintain their Tcore-low, such as increasing metabolic rate, constricting skin blood vessels, or shivering. Furthermore, Tcore-low increases the individuals' "coldness sensations" throughout the body, hence the frequent reports from ANs and SSs of "feeling cold." To eliminate these uncomfortable "coldness sensations" and, importantly, to maintain Tcore-low, ANs, and SSs "select" different thermoregulatory behavioral strategies. It is proposed that the primary differences between AN and SS, based on genetics, now manifest due to the "selection" of different thermo-regulatory behaviors. AN patients (ANs) "select" hyperactive behavior (HyAc), which increases internal metabolic heat and thus assists with maintaining Tcore-low; in harmony with hyperactive behavior is a lively mood. Also related to this elevated arousal pattern, ANs experience disrupted sleep. In contrast, SS individuals "select" a passive thermo-behavioral strategy, "shallow torpor," which includes reduced activity, resulting in energy conservation. In addition, this inactivity aids in the retention of generated metabolic heat. Corresponding to this lethargic behavior, SS individuals display a listless mood and increased sleep.

Conclusion

Initial similarities between the two are attributable to physiological changes related to extreme weight loss. Differences are most likely attributable to genetically programmed "selection" of alternate thermoregulatory strategies, primarily to maintain Tcore-low. However, if acute AN is prolonged and evolves into a chronic condition, AN will more closely align with starvation and more precisely reflect SS symptomology.

Remission from Chronic Anorexia Nervosa With Ketogenic Diet and Ketamine: Case Report

BACKGROUND

Chronic anorexia nervosa is a tragic disease with no known effective pharmacological or behavioral treatment. We report the case of a 29 year-old woman who struggled with severe and enduring anorexia nervosa for 15 years, and experienced a complete recovery following a novel treatment of adopting a ketogenic diet followed by ketamine infusions. Her remission has persisted for over 6 months.

CASE PRESENTATION

At age 14.5, the patient embarked on an effort to "eat healthy." She quickly lost control of the dieting, developed associated compulsions and obsessions about food, body dissatisfaction, emotional lability, and lost nearly 13.6 kilograms (30 pounds). She was hospitalized for 6 weeks, and while she regained some weight, she did not attain full weight restoration. For 15 years, she continued to eat in a restrictive manner, exercise compulsively, and have intermittent periods of alcohol dependence. Nevertheless, she always hoped to get well, and at age 29, she began a novel treatment for anorexia nervosa.

CONCLUSIONS

This is the first report of a ketogenic diet used specifically for the treatment of anorexia nervosa, followed by a short series of titrated IV ketamine infusions leading to complete remission of severe and enduring anorexia nervosa, with weight restoration, and sustained cessation of cognitive and behavioral symptoms, for 6 months. Although these treatments were used sequentially the relationship between these modalities, and possible synergy, is unclear, and deserves further study. Complete and sustained remission of chronic anorexia nervosa is quite rare, and the novel use of a ketogenic diet and IV ketamine treatment in this potentially lethal condition suggests avenues for further research, and hope for patients and their families.