Long-term follow-up of deep brain stimulation for anorexia nervosa

Anorexia nervosa (AN) is an eating disorder characterised by pervasive preoccupations with body weight, shape and size. This translates into caloric restriction and/or excessive physical exercise to obtain and maintain a low body mass index (BMI). Pharmacotherapy has no sustained impact on weight or AN psychometrics. Conventional psychiatric treatment fails in about half, and 30%–50% of weight-restored patients relapse within a year.1 2 Since 2011, we have investigated deep brain stimulation (DBS) targeting the subcallosal cingulate (SCC) in patients with chronic, severe and highly refractory AN.3 4 We previously published 9-month outcomes in six patients3 and 1-year outcomes in 16 patients.4 We demonstrated short-term safety and acceptability of SCC–DBS and observed affective symptom improvements and cerebral glucose metabolism changes in key AN-related structures. Moreover, average BMI increased by 3.5 kg/m2 from baseline after 1-year of SCC–DBS.3 4 Given the invasive and experimental nature of SCC–DBS and the characteristic waxing and waning course of AN, we wished to report our long-term observations. This was a prospective long-term extension of a previously published open-label trial (ClinicalTrials.gov NCT01476540) conducted at the University of Toronto.3 4 Research Ethics Board approval (#10-0991-A) and informed consent were obtained. Inclusion and exclusion criteria, surgical details, adverse event classification and DBS programming algorithms have been described previously.3 4 In the current study, we exclusively analysed patients who had been stimulated for ≥3 years as of 1 October 2018. The primary outcome was procedure safety and acceptability. Secondary outcomes were long-term changes in BMI, eating behaviour, psychometrics (Hamilton Depression Rating Scale (HAMD), Beck Depression Inventory (BDI), Beck Anxiety Inventory (BAI), Yale-Brown Obsessive Compulsive Scale (YBOCS), Yale-Brown-Cornell Eating Disorder Scale rituals …