Neuromodulation appears to be emerging gradually as a new therapeutic
field in psychiatric treatment. It encompasses neuropsychiatric medical
devices, such as vagus nerve stimulation (VNS), transcranial magnetic
stimulation (TMS), deep brain stimulation (DBS), and electroconvulsive
therapy (ECT). As a therapeutic approach to affective disorders,
neuromodulation shifts the focus from the monoamine synapse to neural
circuitry of the brain, which is dysregulated in depression. This neural
circuitry has been elaborated on over the course of 15 years of
neuroimaging research in mood disorders and is now believed to encompass
disturbances in a frontolimbic network. These include reduced
metabolism and blood flow in the prefrontal cortex and anterior
cingulate and pathologically increased activity in the subgenual
cingulate and amygdala.VNS is an implanted device that has established
efficacy in pharmaco-resistant epilepsy. It was approved by the FDA for
the treatment of severe, recurrent unipolar and bipolar depression in
July of 2005. VNS adopts a bottom-up approach to modulating the neural
circuitry of depression by stimulating vagal afferent fibers in the neck
, which carry impulses to the brain stem to target there the locus
ceruleus and dorsal raphe nucleus. Now that VNS has moved beyond the
experimental phase and into the clinic, psychiatrists are faced with
deciding who is an appropriate patient for this surgical implant and how
to integrate VNS into existing treatment in order to optimize both
efficacy and safety.This review of VNS will assess the efficacy and
safety data that led to the FDA approval. We will also review for the
busy clinician how VNS is likely to translate into clinical practice as
a treatment option for patients in need who are suffering from severe
depression.
field in psychiatric treatment. It encompasses neuropsychiatric medical
devices, such as vagus nerve stimulation (VNS), transcranial magnetic
stimulation (TMS), deep brain stimulation (DBS), and electroconvulsive
therapy (ECT). As a therapeutic approach to affective disorders,
neuromodulation shifts the focus from the monoamine synapse to neural
circuitry of the brain, which is dysregulated in depression. This neural
circuitry has been elaborated on over the course of 15 years of
neuroimaging research in mood disorders and is now believed to encompass
disturbances in a frontolimbic network. These include reduced
metabolism and blood flow in the prefrontal cortex and anterior
cingulate and pathologically increased activity in the subgenual
cingulate and amygdala.VNS is an implanted device that has established
efficacy in pharmaco-resistant epilepsy. It was approved by the FDA for
the treatment of severe, recurrent unipolar and bipolar depression in
July of 2005. VNS adopts a bottom-up approach to modulating the neural
circuitry of depression by stimulating vagal afferent fibers in the neck
, which carry impulses to the brain stem to target there the locus
ceruleus and dorsal raphe nucleus. Now that VNS has moved beyond the
experimental phase and into the clinic, psychiatrists are faced with
deciding who is an appropriate patient for this surgical implant and how
to integrate VNS into existing treatment in order to optimize both
efficacy and safety.This review of VNS will assess the efficacy and
safety data that led to the FDA approval. We will also review for the
busy clinician how VNS is likely to translate into clinical practice as
a treatment option for patients in need who are suffering from severe
depression.
