‘How does the immune system interact with the nervous system?’. Denoting the study of interactions between the immune and nervous systems, the wordis quite the mouthful. Though decades old, its sparse track record of signal accomplishments is a major reason the field remains niche and not yet mainstream. Funnily enough though, substantial data in recent years shows immune-nervous system interactions to be integral for maintaining normal health. Consider two prominent examples,
- Stimulating the . Among other things, experimental model studies show it could even alter the course of irreversible sepsis.
- The effect.
Vagus nerve: A Master Communicator Between Immune & Nervous Systems?
In 2000, a team led byshowed they could reverse what was assumed to be irreversible septic shock simply by stimulating the vagus nerve in a timely manner after injecting mice with a lethal dose of ( ). Seventeen years later, how neural circuits might control both degree and type of inflammation (see below from ) is beginning to attract major research and pharma interest so much so therapies based on vagus nerve stimulation may even be realistic for a variety of inflammatory and autoimmune disorders at some point in the future.
Placebos: Some Examples of Effectiveness in Inflammatory Disorders & Infections
Inflammatory disorders such as(IBS), other (IBD), and allergies such as asthma are increasingly a bane in developed countries. Clearly, immune system dysfunction is a major component of such inflammatory disorders. While not so apparently obvious, nervous system involvement is also increasingly undeniable. For example, over the past decade, a series of increasingly ingenious collaborative studies by prominent placebo effect researcher as well as studies by others have shown a prominent role for placebos in alleviating symptoms of inflammatory disorders. Since the brain is a key mediator of the placebo effect, this implicates nervous system function in influencing the course of inflammatory disorders.
- A 2008 study ( ) on 262 randomly assigned IBS patients compared effect of two different types of placebos to No Rx (evaluation and observation alone) for 3 weeks. Placebos were sham acupunctures given by a practitioner who either interacted little or was warm and attentive. Symptom relief ranged from 28% in the no Rx group to 44% (limited interaction) and 62% (warm and attentive) in those who were randomly assigned to the two placebo groups.
- A 2010 study from the same group, again with IBS patients, tried a groundbreaking tack, an open-label placebo described as (see below from ),
‘inert or inactive pills, like sugar pills, without any medication in it’
with the patients being told (see below from)
‘placebo pills, something like sugar pills, have been shown in rigorous clinical testing to produce significant mind-body self-healing processes’.
Patients in the placebo group thus knew they were getting placebos with the Rx provider explaining (see below from),
‘(1) the placebo effect is powerful, (2) the body can automatically respond to taking placebo pills like Pavlov’s dogs who salivated when they heard a bell, (3) a positive attitude helps but is not necessary, and (4) taking the pills faithfully is critical’
An average of as many as 75% experienced symptom relief (n=37) compared to 28% in the No Rx group (n=43).
- A 2011 study ( ), again led by Kaptchuk, this time on asthma patients, compared patients who got a bronchodilator inhaler, a placebo inhaler, placebo (sham) acupuncture or no treatment. While only the bronchodilator inhaler yielded objective symptom improvement (~50%), namely, better forced expiratory volume, patients who got the two placebo Rx reported subjective symptom improvement (~21%) over the No Rx group.
- A 2009 study ( ) on 350 patients with the common cold found shorter duration and less severity in those patients who perceived their doctors to be highly empathic.
- A 2011 open-label study on the common cold divided patients into 4 groups (see below from ),
‘(1) those receiving no pills, (2) those blinded to placebo, (3) those blinded to echinacea, and (4) those given open-label echinacea’
and the authors concluded (see below from),
‘Participants randomized to the no-pill group tended to have longer and more severe illnesses than those who received pills. For the subgroup who believed in echinacea and received pills, illnesses were substantively shorter and less severe, regardless of whether the pills contained echinacea.’
1. Borovikova, Lyudmila V., et al. “Vagus nerve stimulation attenuates the systemic inflammatory response to endotoxin.” Nature 405.6785 (2000): 458-462.
2. Fox, Douglas. “The electric cure.” (2017): 20-22.
3. Kaptchuk, Ted J., et al. “Components of placebo effect: randomised controlled trial in patients with irritable bowel syndrome.” Bmj 336.7651 (2008): 999-1003.
4. Kaptchuk, Ted J., et al. “Placebos without deception: a randomized controlled trial in irritable bowel syndrome.” PloS one 5.12 (2010): e15591.
5. Wechsler, Michael E., et al. “Active albuterol or placebo, sham acupuncture, or no intervention in asthma.” New England Journal of Medicine 365.2 (2011): 119-126.
6. Rakel, David P., et al. “Practitioner empathy and the duration of the common cold.” Family medicine 41.7 (2009): 494.
7. Barrett, Bruce, et al. “Placebo effects and the common cold: a randomized controlled trial.” The Annals of Family Medicine 9.4 (2011): 312-322.