Ethical considerations in using brain stimulation to treat eating disorders

Eating disorders (EDs), such as anorexia nervosa (AN), bulimia nervosa (BN), and binge eating disorder (BED) are characterized by pathological eating behaviors and body image disturbance. These disorders are associated with high levels of mortality and morbidity, as well as significantly impaired quality of life (Arcelus et al., 2011). EDs are often associated with young adulthood, with the disorder typically being first diagnosed when the person is 15–19 years old (Hoek and van Hoeken, 2003; Hudson et al., 2007). Recently, there has been increased interest in the neurobiology of EDs as an insight into the mechanisms of pathological eating behavior, and as a potential avenue for treatment (Kaye et al., 2010). Brain-based interventions for EDs have in the past involved highly invasive deep-brain stimulation (DBS), in which surgically implanted electrodes deliver electrical pulses to brain areas such as the cingulate cortex (Israel et al., 2010) or the nucleus accumbens (Wu et al., 2013). These surgeries have proved reasonably effective in the small number of reported cases. However DBS has a number of problems that make it less attractive as a treatment option: DBS exposes the person to the risks of surgery; the potential side-effects are more serious; and it is difficult to adjust or to reverse the treatment. For these reasons, there is much interest in a treatment that modulates brain activity but that does not expose the patient to such serious side-effects. There has recently been an increase in interest in the use of so-called non-invasive brain stimulation to treat EDs. These techniques, principally transcranial magnetic stimulation (TMS) and transcranial direct current stimulation (tDCS), use magnetic or electric fields to transfer energy across the skull, and so to modulate neural activity. Here, we explore the rationale for using TMS/tDCS in EDs, and argue that many ethical and safety issues must be clarified before widespread adoption of these techniques is possible