American scientists have shown the effectiveness of open-placebo in the treatment of negative emotional responses. For this, they were shown to the participants of his experiment, frightening images and evaluated their reactions — with the help of surveys and measurement of evoked potentials on EEG, they sprinkle a little in a nose spray, nothing. Compared with the control group, which didn’t say anything about placebo and its effects, participants that used an open placebo, failed to reduce the indicators of emotional stress. Due to the fact that the open placebo changed and subjective psychological and objective response according to EEG, the effect can be called psychobiology, write scientists in Nature Communications.
Work placebo in the treatment of certain diseases and conditions is provided mainly psychological effect: if the patient is convinced that treatment will help him, he will really become better. Interestingly, the placebo effect is observed in cases where placebos are used openly — that is, telling patients they take the “dummy” and explains he is apparently also a psychological effect.
The effectiveness of the use of an open placebo is usually measured only subjectively: patients themselves report that it becomes easier (with the help of standardized questionnaires or interviews). According to objective psychological and physiological indicators of the efficiency of the open placebo did not previously prove: largely because it check on conditions and diseases that are difficult even ordinary, closed a placebo.
Darwin Guevarra (Guevarra Darwin) from the University of Michigan and his colleagues decided to check the work of the open placebo in the treatment condition, which is accurately measured by conventional placebo — emotional disorders. They conducted an experiment with the participation of 68 people, which were divided into two groups: before the experiment were given a brochure about the neurological basis of pain and the second on the work and effectiveness of a placebo. The first group, therefore, was a control, while the latter is active, with the use of an open placebo.
Afterwards, the participants were sprinkled in the nose spray: first, the control group, said that the spray is needed in order to improve the visibility of their psychological parameters, and the second group, the open placebo, reported that a spray is needed in order to improve their emotional state during the experiment. They also said that, despite the fact that they are taking a placebo, which in fact should not operate, the effect may still be that case that person will think that a placebo therapy will help him.
During the experiment, participants were shown pictures of either neutral or fearful — those who had worsen the emotional state of the participants. After each image the participants had on a scale from 1 to 9 to note how negative emotions cause the image.
It turned out that subjective indicators open a placebo in fact, effectively reduced the level of negative emotions when viewing images compared with the control group (p < 0.0001), but when viewing neutral pictures, this effect was not observed.
In the second experiment, (218 participants), the researchers decided to test the effect of open placebo on an objective measure of emotional response — late positive potential (LPP), occurring approximately 300 milliseconds after the presentation of the stimulus and persisting for up to six seconds. The task was similar: participants were shown neutral or gruesome images and measured the amplitude of the late positive potential by means of EEG.
The amplitude of the measured potential immediately after viewing the images between the groups did not differ, which suggests that all participants carefully looked at the picture. After, however, the group of open placebo the amplitude of the potential beginning significantly (p < 0.01) decrease in comparison with the control group.
The researchers concluded that the use of open placebo in the treatment of emotional disorder in fact effective. It is important to note that this efficiency is not only subjective (otherwise we could only talk about the bias of the response, where the participants ‘ answers depend on what, in their opinion, they expect the experimenter), but also objective, that is, the effect of open placebo this particular therapy psychobiology.
More details about the work placebo, its history and effectiveness you can read in our materials: “Lie to me if you can” and “to Relieve, not to cure”.