Major depression has long been a disorder weighing down on its victims, but fascinating neuroscientists. Can we use the placebo effect to leave the confines of a depressed world? What exactly lies behind the mechanisms of the placebo analgesic effect? To find out, researchers compared the effect of fluoxetine and a placebo and using neural imaging techniques, compared which regions of the brain showed activity/change at the beginning of the study, at six weeks, and at the end. What they found was that each treatment method caused an increase in activity in the prefrontal and posterior cingulate and decreases in subgenual cingulate. Fluoxetine worked better, and the results of the placebo were inconclusive. Although not tested in an extended study, researchers also compared the effect of various psychotherapies as opposed to placebos and found that they each affected different regions of the brain and that, unfortunately the placebo effect only worked for a little while.
But hold up! If our emotions are strictly based on the balance of chemicals in our brain, then how could we possibly fool ourselves of how we really feel even for a second? The placebo analgesic effect is when our brains signal to generate endorphins in order to alleviate pain.
The expectation of getting better plays a huge role in how well the placebo effect works and the way this is tested is through the use a drug called naloxone. Naloxone counters the effect of opioids and is used to reverse heroin/morphine overdoses in modern clinical practice. It was found that in patients where the placebo analgesic was brought on by strong expectations, the response could be blocked by naloxone. However, if the expectation cues were decreased, naloxone would not work. This concludes that in order for naloxone to work, there needs to be a large amount of endogenous opioid concentration.
Let�??s delve into this a little further. If the patients were exposed to various opioid drugs, the placebo effect could be reversed by naloxone, but if they were not, they were insensitive to naloxone. It can be concluded that naloxone only works in certain physiological conditions.
A typical side effect of opioids is respiratory depression. It was hypothesized that a placebo could mimic the effects of a drug which causes mild respiratory depression. Repeated injections of buprenorphine during the study and then a final injection of a placebo showed that the placebo was able to induce respiratory depression in the same way that the opioid did.
Placebo analgesics only work on certain people and in certain physiological conditions. But we know that they can induce extreme physiological changes, for the better or worse. Further studies need to be conducted to prove how exactly our brain can practice �??mind over matter�??.
all info was taken from http://www.jneurosci.org/content/25/45/10390.full.pdf+html