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Monday, September 10, 2007

Vagus Nerve Stimulation (VNS)


VNS received FDA approval in July 2005 for adjunctive, long-term use in chronic or recurrent major depression in adult patients with an inadequate response to at least four antidepressant treatments. You could say it is an option after other treatments for depression has failed, these options for treatment resistant depression are summarized in another article on this blog: 9 steps for treatment resistant depression.
Time for an update. A review of important articles from a scientific point of view. Not an exhaustive literature search.

Vagus Nerve Stimulation for the long term efficacious?

Two unblinded trials have been published with (n=59) treatment resistant depressed patients. Over 30% were responders after 10 weeks. Response was defined as at least a 50% reduction of the Hamilton Depression Rating Scale, a depression severity scale. In a long term naturalistic follow-up of this study, 30 patients received an additional 9 months of stimulation. Response was sustained, and remission rates were significantly improved (from 17% to 29%). Remission is defined as a score on the HDRS of 10 or less, that is to say these patients were free of depressive symptoms. This suggests that the efficacy of VNS is probably something that takes time. Patients might benefit if VNS is given during a longer period of time.

Analysis of a 1 year follow-up from patients receiving additional VNS in an open label study showed that response increased per month during the 12-month follow-up. Response defined as decrease of the average HDRS score. This response criterion is very sensitive, clinical relevance is difficult to interpret.

The short term results from the placebo controlled study of VNS combined with usual standard of care the antidepressant effect of VNS could not be established. This study was performed before the open label long term study mentioned above.

Vagus Nerve Stimulation
What is VNS?
Bipolar electrodes are attached to the left vagus nerve within the neck. These electrodes are connected to a generator. This generator is a small device, it is implanted subcutaneously into the left chest wall. The generator is programmed to deliver mild electric pulses in continuous cycles, typically with 30 seconds of stimulation followed by 5 minutes off. The device can be set non-invasively by the treating physician who uses an external device to change the "dose".
It could be that the antidepressant effect is achieved by influencing the amygdala and other limbic structures via projections from the vagus nerve.

The device and the electrodes on the vagus nerve are implanted during surgery by a neurosurgeon, mostly during general anesthesia.

Side-effects of Vagus Nerve Stimulation
During the short stimulation (30 seconds) voice alteration can occur as well as hoarseness, dyspnoe and cough.
There can be a slight cosmetic change in the appearance of the chest after generator implantation.

No clear acute relief of depression shown yet. In treatment resistant depression maybe an option for the longer term.

Literature used

1. Effects of 12 months of vagus nerve stimulation in treatment-resistant
depression: a naturalistic study.
Biol Psychiatry. 2005 Sep 1;58(5):355-63.

Rush AJ, Sackeim HA, Marangell LB, George MS, Brannan SK, Davis SM, Lavori P, Howland R, Kling MA, Rittberg B, Carpenter L, Ninan P, Moreno F, Schwartz T, Conway C, Burke M, Barry JJ.
Comment in:
Biol Psychiatry. 2006 Dec 15;60(12):1382; author reply 1382-3.

2. Vagus nerve stimulation for treatment-resistant depression: a randomized,
controlled acute phase trial.
Biol Psychiatry. 2005 Sep 1;58(5):347-54.
Rush AJ, Marangell LB, Sackeim HA, George MS, Brannan SK, Davis SM, Howland R, Kling MA, Rittberg BR, Burke WJ, Rapaport MH, Zajecka J, Nierenberg AA, Husain MM, Ginsberg D, Cooke RG.
Comment in:
Biol Psychiatry. 2006 Dec 15;60(12):1382; author reply 1382-3.

3. Vagus nerve stimulation (VNS) for major depressive episodes: one year outcomes.Biol Psychiatry. 2002 Feb 15;51(4):280-7.
Marangell LB, Rush AJ, George MS, Sackeim HA, Johnson CR, Husain MM, Nahas Z, Lisanby SH.

4. Vagus nerve stimulation (VNS) for treatment-resistant depression: efficacy, side
effects, and predictors of outcome.
Neuropsychopharmacology. 2001 Nov;25(5):713-28.
Sackeim HA, Rush AJ, George MS, Marangell LB, Husain MM, Nahas Z, Johnson CR, Seidman S, Giller C, Haines S, Simpson RK Jr, Goodman RR.

Other articles about Neurostimulation in treatment resistant depression on this blog:

1. ECT, for information about ECT this blog delivers a lot of articles, one here and the other over here.

2. More about Magnetic Seizure Therapy in a recent post on this blog.

3. About rTMS


herb said...

Dear Dr. Shock,

No clear acute relief of depression shown yet. In treatment resistant depression maybe an option for the longer term.” --- Dr. Shock

I would like to take this opportunity to share several points of view and the first being your use of the term TRD (Treatment Resistant Depression). While it seems you, I and a number of the leading psychiatric researchers and practitioners utilize this terminology in the United States and elsewhere, CMS (Centers for Medicare & Medicare Services) in the U.S. issued a treatise essentially denigrating you and your profession and specifically noted in their denial of the VNS treatment option for depression that there is no such medical term as “TRD” (Treatment Resistant Depression) in the DSM IV amongst other statements.

Kindly see the below listed link for the actual document:

As additional evidence of the clinical benefits from VNS Therapy being obtained and observed by your colleagues and peers may I suggest some of the following readings?

New Study Supports Efficacy of Vagus Nerve Stimulation for Treatment-Resistant Depression

In my opinion the timing of VNS Therapy for MDD (Major Depressive Disorder) was inopportune and became another of what I refer to as the “Power/Politics/Money Games” being played in this country without regard for the wellbeing of the citizens of the U.S.

$12 Billion is being expended on warring so how can this current administration justify any new treatments for those suffering serious mood disorders when mental health has been discriminated against for centuries.

The fact is this therapy too is not a panacea like all the other therapies but what it does offer for those who are considered the “worst of the worst” a reasonable percentage response and most amazingly, like no other therapy, it also offers long-term remission previously unheard of for this unique population of seriously ill patients.

After battling my spouse’s illness for some 37 years, the previous 7 years have been nothing short of remarkable through the use of the VNS Therapy. The first 3 years my wife was depression free without the use of any psychotropic medications. The past 4 years she’s had several short-lived relapses while also utilizing low doses of psychotropic medications but when compared to the previous 37 years her quality of life has been “pretty remarkable”. The same long-term benefits are being obtained by a number of patients with whom I have the good fortune to collaborate. As one patient has explained it to me in response to several physicians claiming a “placebo effect” is the fact this individual has had "one year placebo effects six years in a row".

“No clear acute relief of depression shown yet.” --- Dr. Shock

Based upon my knowledge of those who have responded I couldn’t disagree with you more and so too psychiatrists attending to these patients in their clinical practices.


Dr. Shock said...

Every opportunity to battle against depression is worth researching.
The gap between CMS and patients is large as I gather from your information.
Depressed patients should unite and stand up for their right on new cures.
Thanks for your valuable comment, regards,

Dr Shock

Anonymous said...

Mr. Stein has once again failed to disclose his finanial ties with the maker of the device.

herb said...

One of the very interesting aspects of the Internet and message forums and blog sites is the freedom with which individuals attempt to disparage and/or defame one’s character behind the cloak of anonymity and obvious ignorance as displayed by this particular anonymous individual through his/her lack of research.

Having shared my name and views freely on the Internet and with transparency as to any relationship I might have or have not with the sponsor of the therapy, Cyberonics or any other entity, are clearly stated for all to read in my disclosures in a section of the website I host from its inception. One need only read.

Through these many years of proactive mental health advocacy and activism I’ve had the fortune or misfortune depending upon how one looks at the subject to have attracted a number of followers and some more interested in following me from forum to forum and attacking me personally rather than discussing the subject of the VNS Therapy, alternatives and/or mental health and wellness. There was recently another instance of a similar episode on the blog site of “The Trouble With Spikol” in which Ms. Liz Spikol recognized the aberrant behavior and removed the anonymous individual’s comments and in turn posted her remarks relating to the matter which can read in the following link:

What would be nice is if this particular anonymous intellect was capable and could research my disclosure statements and then come back to quote and report to all the allegations and/or innuendos made in his/her posting above.


Dr. Shock said...

Thanks for the link I have added her blog to my reader.
To my opinion your reply to the previous posting says enough.
Regards Dr Shock