The placebo effect is the positive effect (clinical improvement) following the administration of an inert treatment (the placebo) with no specific therapeutic properties (water, flour, etc.). What matters is not so much the inert treatment but rather the psychosocial context around the patient, which induces positive expectations of benefit. In other words, a placebo is the whole ritual of the therapeutic act, which is made of many psychological and social factors. https://www.youtube.com/watch?v=ZHeF7rYz7uY

Whereas a placebo effect is related to positive effects, the nocebo effects are attributable to negative expectations, which, in turn, lead to clinical worsening.

https://pubmed.ncbi.nlm.nih.gov/23899563/

Some possible implications are represented by the administration of placebos interspersed among real treatments, according to a paradigm such as “drug-drug-drug-placebo-drug-drug-placebo-drug-etc.” In the long run, this may lead to a reduction of drug intake.

https://physoc.onlinelibrary.wiley.com/doi/full/10.1113/JP271322

There are people responding to placebos and people who do not. It is not clear why this happens, but personality traits, genetic factors, and social factors may play an important role. This is a future challenge for placebo research.

Whenever psychological factors are involved, such as in pain, motor performance, anxiety, depression, the placebo effect is important. Conversely, placebos cannot kill the bacteria of pneumonia, nor can they prevent pregnancy, nor can they stop cancer growth.

Not exactly. There are many physiological and biochemical effects both in the brain and in the whole body, such as the release of endorphins and endocannabinoids.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3055515/

Learning is important. If a drug is given several days in a row and then replaced with a placebo, the placebo effect is usually huge. By contrast, if a placebo is given for the first time, the placebo effect is smaller, or it does not occur at all.

https://www.nature.com/news/parkinson-s-patients-trained-to-respond-to-placebos-1.19341

The very definition of placebo effect is that it is a true psychobiological effect. Regression to the mean may play a role, sometimes important, but it has nothing to do with the real psychological placebo effect.

No, our research is only aimed at better understanding the psychological component of any treatment, be it pharmacological or not. Complementary and alternative medicine is outside mainstream medicine because, as far as we know today, they lack rigorous scientific evidence.

Yes, the social encounter between the therapist and the patient plays a crucial role. Any word, behaviour, the attitude of the therapist may potentially influence the therapeutic outcome and the course of a disease.

Yes, the psychological and social effects of mass phenomena are very important, as they may influence how we approach and deal with vaccination. Indeed, cultural factors play a role virtually in all circumstances.

Pessimistic doctors are characterized by bad behaviours and attitudes, and these in turn can be transmitted and communicated to their patients, either consciously or unconsciously. If I am a patient and perceive uncertainty in my doctor, this may have a tremendous impact on my psychological status.

Yes, if I know everything about what is happening in my body, my attention will be directed to my body more than others. And this may increase my perception of symptoms and pathological states.

There are treatments, either pharmacological or not, that are more effective than placebos (just consider antibiotics and powerful painkillers). Therefore, in these cases, it is better to use effective treatments, as they can improve the clinical outcome more than placebos.