Objective: The side effects of drug therapy are not only directly attributable to the drugs taken but may also be caused by psychological phenomena. One such phenomenon is the nocebo effect, wherein adverse effects are triggered by the patient’s recognition of symptoms. The patient’s development of side effects may be influenced by the pharmacist’s explanation of side effects, but it is not known how many pharmacists are actually aware of the nocebo effect. Therefore, this survey aimed to clarify pharmacists’ awareness of the nocebo effect and the extent to which they utilize their knowledge of this phenomenon when providing medication guidance, and to determine whether their awareness influences explaining of the side effects at medication guidance.Methods: A questionnaire survey was conducted using Google Forms. After defining the nocebo effect, the respondents were asked what points they note when explaining side effects, whether they were aware of the nocebo effect, and in what types of patients they tend to be aware of it. Simple tabulations were performed for each item, and subgroup analyses were performed according to the level of awareness of the nocebo effect.Results: Of the 100 participants, 65did not know the term “nocebo effect”. However 82 provided medication guidance considering the nocebo effect phenomenon, and many pharmacists who were familiar with the nocebo effect responded that it should be taken into consideration when providing drug guidance. Side effects of particular concern related to the nocebo effect are subjective symptoms such as nausea and vomiting, anxiety and depression, and drowsiness and somnolence; patients with neurotic tendencies or high anxiety also require special attention.Conclusion: Although the term “nocebo effect” is not well known by pharmacists, the phenomenon itself is widely recognized. Many pharmacists reported that understanding the nocebo effect when explaining the side effects, therefore medications leads to improved therapeutic efficacy.

Objective: The placebo effect can enhance the response to treatment, even in the absence of pharmacological ingredients. One possible factor explaining the likelihood of the placebo effect in individuals is genetic polymorphisms in neurotransmitters. This study focused on gene polymorphisms in the catechol-O-methyltransferase (COMT) as an interindividual variable of the placebo effect.Design・Methods: All 120 participants were explained the effects of caffeine, including its ability to ameliorate drowsiness and increase concentration, and then given a placebo (lactose). The onset of the placebo effect was measured in terms of the degree of caffeine-reduced sleepiness using subjective indices of the Stanford Sleepiness Scale (SSS) and a feeling of drowsiness-Visual Analogue Scale (VAS). The mechanism of the placebo effect was objectively examined in terms of changes in cerebral blood flow in the prefrontal cortex of the brain. In addition, we investigated participants’ susceptibility to the placebo effect by examining genetic polymorphisms in COMT.Results: After taking the drug, sleepiness on the SSS and VAS was significantly improved (p＜0.001), although there was no change in prefrontal cortex activity. Among the 120 participants, 63 had a Val/Val-type polymorphism in COMT (52.5%), 45 had a Val/Met-type (37.5%), and 12 had a Met/Met-type (10.0%). There were no significant differences among COMT gene polymorphisms in the subjective measures of SSS and VAS. However, there was a tendency for the cerebral blood flow changes to be larger in the left hemisphere of the brain in individuals with the Met/Met type.Conclusion: There seems to be a relationship between prefrontal cortex activity and genetic polymorphisms. In particular, there may be a correlation between the expression of a placebo effect and COMT gene polymorphisms.