Treatment-resistant, severe anorexia gets a jolt
medwireNews: A neurosurgical implant has been used for the first time to explore the therapeutic potential of deep brain stimulation (DBS) in treating patients with severe and lasting anorexia nervosa that is resistant to other treatments.
A phase 1, prospective trial showed that bilateral DBS of the subcallosal cingulate region of the brain - a DBS target for resistant depression - produced relatively few complications in treating six female patients (mean age of 38 years) who suffered from a chronic, severe, and treatment refractory form of the psychiatric disorder.
"DBS might be able to change the natural history of the illness, with the potential to improve clinical outcomes in some patients," write Andres Lozano (University of Toronto, Ontario, Canada) and colleagues in The Lancet. "However, our initial results need to be investigated further in randomized, controlled trials."
Electrical stimulation would last for 9 months, beginning at 3.5 V, pulse width 90 µs, and frequency of 130 Hz. The amplitude was then calibrated based on patient and physician feedback.
The lone serious adverse event was a seizure during programming 2 weeks after surgical implantation of the electrode, while less serious events included panic attack during surgery, nausea, cardiac air embolus, and pain.
Although all the patients initially lost weight and fell below their preoperative body mass index (BMI) at 2 months, three patients eventually had BMIs that were higher than their baseline at 9 months; which was the longest period of sustained BMI increase since the onset of their illness. The remaining three retained their baseline measure.
"The initial weight loss argues against a primary effect of DBS on hunger, appetite, or metabolic rate," write the authors. "It also suggests that there is little in the way of a placebo-related benefit to the surgery."
There were substantial reductions in depression, obsessive compulsive, and anxiety scores over the course of DBS, leading Lozano and team to suggest that the clinical effect "might be mediated by a restoration of affective equilibrium," so that DBS disrupts the factors that maintain illness.
In an accompanying commentary, Janet Treasure and Ulrike Schmidt, from King's College, London in the UK, point out that DBS's target choice and mechanism of action still remain an open question in treating severe cases of anorexia nervosa. But the improvement in affective and obsessional symptoms observed in this small sample of patients is still "of key importance" in showing DBS's potential to be "not just another treatment designed to fatten them up without making them feel better."
By Peter Sergo, medwireNews Reporter