Long-term study shows VNS effective depression therapy
New long-term findings demonstrate that patients with difficult to treat chronic or recurrent depression continue to respond to vagus nerve stimulation (VNS) therapy for up to two years.
Dr.
Mark George presents long-term data on the effectiveness of vagus nerve
stimulation (VNS) in treating people with chronic and recurrent depression
to journalists and scientists all over the world through a live webcast
originating from MUSC's Basic Science Building.
Results from the 60-patient long-term study, led by Mark George, M.D., distinguished professor, departments of Psychiatry, Radiology and Neurology, indicate that extended treatment with VNS is associated with the elimination or reduction of depressive symptoms and an improved ability to perform daily functions.
The study, conducted to determine whether the promising results seen in an acute phase (three month) pilot study were sustained after one to two years of treatment with VNS, used remission and response rates as the primary indicators of success.
Response means that a patient’s depression symptoms were cut in half; remission means that a patient has become virtually symptom-free.
The study found that depressed patients with VNS improved over time in terms of remission and response and also improved in their ability to function:
- 27 percent of patients were in remission after one year, increasing from 15 percent at the end of the acute study;
- 45 percent of patients responded to treatment after one year, increasing from 31 percent at the end of the acute study; and
- 54 percent of patients responded to treatment after two years, increasing from 46 percent at the one-year mark.
Depression is a mental illness of global proportions, affecting approximately 340 million people worldwide and more than 18 million American adults. Furthermore, major depression is a leading cause of disability.
The illness is characterized by sad moods, loss of interest or pleasure, feelings of guilt or low self-esteem, disturbed sleep and appetite, low energy level and the decreased ability to concentrate. These problems many times become chronic or recurrent and prevent those affected from performing everyday tasks and family and occupational responsibilities.
“Depression is a chronic, disabling lifelong illness that requires a well-tolerated treatment that provides both acute symptom relief and continued benefits,” stated Harold Sackeim, Ph.D., professor, departments of Psychiatry and Radiology, Columbia College of Physicians and Surgeons and New York State Psychiatric Institute. “Studies of VNS for depression thus far indicate that this therapy may be an option for patients who have not had a positive long-term response to commonly available treatments.”
About VNS
VNS stimulates the limbic system, a group of related brain structures
that affect mood, motivation, sleep, appetite, alertness and other factors
commonly altered by depression.
VNS is delivered to the left cervical vagus nerve by a stopwatch-sized generator—the NeuroCybernetic Prosthesis (NCP) System—implanted just under the skin in the left chest area. VNS delivers pre-programmed, mild, intermittent electrical pulses to the left vagus nerve 24 hours a day. The implantation procedure takes approximately one hour and usually requires no overnight hospitalization.
VNS is safe and does not cause the side effects normally associated with depression medications, such as weight gain, loss of sexual function, cognitive impairment and insomnia.
Side effects associated with VNS typically occur only when stimulation is on. They include voice alteration, shortness of breath, neck discomfort and coughing, all of which are reported less frequently over time.
The first patient with depression to be treated with VNS was implanted at MUSC in July 1998, and MUSC researchers have continued to pioneer VNS as a treatment for neuropsychiatric disorders, including depression. MUSC researchers have also been combining VNS with real-time functional brain imaging.
VNS with the Cyberonics NCP System was recently approved for sale in the European Union and in Canada as a treatment of depression in patients with treatment-resistant or treatment-intolerant major depressive episodes including unipolar depression and bipolar disorder (manic depression). VNS with the Cyberonics NCP System was approved by the FDA in 1997 for use as an adjunctive therapy in reducing the frequency of seizures in adults and adolescents 12 years of age and older with medically refractory partial onset seizures.
In addition, the NCP System is currently approved for epilepsy in all
the member countries of the European Union, Canada, Australia and other
markets.