placebo effect


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effect

 [ĕ-fekt´]
a result produced by an action.
additive effect the combined effect produced by the action of two or more agents, being equal to the sum of their separate effects.
adverse effect a symptom produced by a drug or therapy that is injurious to the patient.
Bainbridge effect Bainbridge reflex.
Bohr effect decreased affinity of hemoglobin for oxygen caused by an increase of carbon dioxide; the oxyhemoglobin dissociation curve is displaced to the right because of higher partial pressure of carbon dioxide and lower pH. See also Haldane effect.
The Bohr effect causing a shift to the right in the oxyhemoglobin dissociation curve.
Crabtree effect the inhibition of oxygen consumption on the addition of glucose to tissues or microorganisms having a high rate of aerobic glycolysis; the converse of the Pasteur effect.
cumulative effect the action of a drug or treatment resulting from repeated use.
Doppler effect see doppler effect.
experimenter e's demand characteristics.
extrapyramidal e's the side effects caused by neuroleptic medications, including dystonias, parkinsonism, akathisia, and tardive dyskinesia.
Haldane effect increased oxygenation of hemoglobin promotes dissociation of carbon dioxide; see also Bohr effect.
Hawthorne effect a psychological response in which the subjects in a research study change their behavior simply because they are subjects in a study, not because of the research treatment.
heel effect variation in x-ray beam intensity and projected focal spot size along the long axis of the x-ray tube from cathode to anode.
parallax effect the position of the image on each emulsion of dual emulsion film; it is accentuated by tube-angled x-ray techniques.
Pasteur effect the decrease in the rate of glycolysis and the suppression of lactate accumulation by tissues or microorganisms in the presence of oxygen.
photoelectric effect ejection of electrons from matter as a result of interaction with photons from high frequency electromagnetic radiation, such as x-rays; the ejected electrons may be energetic enough to ionize multiple additional atoms.
placebo effect the total of all nonspecific effects, both good and adverse, of treatment; it refers primarily to psychological and psychophysiological effects associated with the caregiver-patient relationship and the patient's expectations and apprehensions concerning the treatment. See also placebo.
position effect in genetics, the changed effect produced by alteration of the relative positions of various genes on the chromosomes.
pressure effect the sum of the changes that are due to obstruction of tissue drainage by pressure.
proarrhythmic effect any new, more advanced form of arrhythmia caused by an antiarrhythmic agent, especially those that produce hemodynamically important symptoms. These arrhythmias occur less than 30 days after initiation of treatment and are not due to a new event such as acute myocardial infarction or hypokalemia.
side effect a consequence other than that for which an agent is used, especially an adverse effect on another organ system.
Somogyi effect see somogyi effect.

placebo effect

n.
The beneficial effect in a patient following a particular treatment that arises from the patient's expectations concerning the treatment rather than from the treatment itself.

placebo effect

a physical or emotional change occurring after a substance is taken or administered that is not the result of any special property of the substance. The change may be beneficial, reflecting the expectations of the patient and often those of the person giving the substance.
Alternative medicine A desired self-healing force released by the mind-body connection
EBM The bias introduced in a study when the patient believes he/she is getting the drug being tested when not, and vice versa
Psychiatry The effect that an inactive or inert substance has on a clinical condition

placebo effect

Placebo response Psychiatry The effect that an inactive or inert substance has on a clinical condition. See Biofeedback, 'Halo' effect, Hawthorne effect, Placebo, Placebo response; Cf 'Nocebo. '.

placebo effect

The often significant, but usually temporary, alteration in a patient's condition, following the exhibition of a drug or other form of treatment, which is due to the patient's expectations or to other unexplained psychological effects, rather than to any direct physiological or pharmacological action of the drug or treatment. The placebo effect has done much to foster the reputation of many valueless forms of treatment.

Placebo effect

Placebo effect occurs when a treatment or medication with no known therapeutic value (a placebo) is administered to a patient, and the patient's symptoms improve. The patient believes and expects that the treatment is going to work, so it does. The placebo effect is also a factor to some degree in clinically-effective therapies, and explains why patients respond better than others to treatment despite similar symptoms and illnesses.
Mentioned in: Biofeedback

pla·ce·bo ef·fect

(plă-sēbō e-fekt)
A response when a treatment or medication with no known therapeutic value is administered to a patient and the patient's symptoms improve due to their belief that the treatment is effective.
References in periodicals archive ?
Among the genes that appear to mediate the placebo effect, five are associated with the chemical messenger dopamine and four are linked with the chemical messenger serotonin.
The biochemical bases for reward: Implications for the placebo effect.
The Placebo Effect offers a clue to what that interpretation might involve when the participants begin to talk about the "ritual" of the medical visit.
The placebo effect -- in which patients who receive an inert substance nonetheless experience some or all benefits of active treatment -- is a topic of growing interest to Parkinson's researchers.
During the past couple of decades, drug treatments for depression have become more effective due to the placebo effect.
Beedie (2007) also reported that 73% of 30 athletes canvassed reported experiencing a placebo effect or similar belief effect at some time during sports training or competition.
For example, a validated sham acupuncture device has a greater placebo effect on subjective outcomes than oral placebo pills (11) and subcutaneous injections of placebo are superior to oral placebos in the treatment of migraine.
of Ottawa), a gastroenterologist who has written several books on his specialty, dispels myths about the placebo effect.
THE power of homeopathic remedies came under fresh challenge yesterday with a team of scientists describing them as weak and producing nothing more than a placebo effect.
A Swiss study has concluded that the remedies from nature have no more healing powers than a placebo effect.
Quinn presents brilliantly the complex matrix of choices made by scientists constructing clinical trials and the way results are interpreted (what does the placebo effect mean, for example?
The powerful placebo effect is linked to the release of a brain chemical involved both in Parkinson's and the sensation of reward, new research reported in the journal Science showed yesterday.