Sammanfattning
Placebo, originally defined as an inactive medication
giving a positive effect, compared to nocebo,
which gives the converse result. Both situations
are based on expectations of a positive or negative
kind. Experimental data from pain research indicates
that placebo responses are caused by stimulation
of endogenous opioids and release of endogenous
dopamine inhibiting receptors for pain and
discomfort in the central nervous system and elicits
wellbeing. Contrary, nocebo may lead to deactivation
of the opioid/dopamine mechanisms and
may increase the pain perception by way of the nerve
transmitter substance, cholecystokinin. Simulataneously,
anxiety and negative expectations may
cause nocebo-related increased activity of stress
related hormones, which affect the endocrine and
immune systems.
The placebo response is now considered as a parttaking
factor in traditional medical treatment and
has been proposed as an explanation for positive
effects experienced by patients taking alternative
medicine. Nocebo responses may follow events,
such as media discussions on allegedly toxic environmental
factors. In the dental clinic, placebo effects
have been reported in cases of myofascial pain
syndrome treatment, whereas nocebo responses
may be responsible for the notion of being poisoned
by mercury from dental amalgam or fearing dental
treatment after earlier traumatizing experiences
in the dental clinic. It is generally accepted that
the quality of patient communication, rituals and
treatment surroundings are of importance to the
placebo/nocebo response.