3 0 0 0 OA 脳が決める効果:プラセボ効果の要因解析からわかること
- 著者
- 井澤 美苗 信野 明美 西村 友宏 登美 斉俊 中島 恵美
- 出版者
- 日本香粧品学会
- 雑誌
- 日本香粧品学会誌 (ISSN:18802532)
- 巻号頁・発行日
- vol.37, no.3, pp.197-200, 2013-09-30 (Released:2014-10-29)
- 参考文献数
- 9
Recent clinical research utilizing noninvasive functional measurement techniques has indicated that placebo effects might be therapeutically useful, because clear responses to placebo administration have been observed in patients' brains. Both physiological and mental states are affected by placebo and a role of brain receptor(s) was suggested. Factors influencing the placebo effect are the Pavlov reaction, expectation, cognition, and conditioning. Further, the nocebo effect is a negative reaction caused by anxiety, which acts as a confounding factor. Different outcomes may be obtained depending upon whether the placebo effect is evaluated in terms of objective or subjective responses. Correlation analyses of outcomes from various clinical trials indicate that placebo improves subjective response more effectively than objective parameters. Psychosocial care of patients is an important aspect of welfare, and a better understanding of the mechanism of the placebo effect will be helpful in this regard. Cognitive therapy is well known to be as efficacious as antidepressant medication for treating depression. Therefore, we studied the relationship between activity in the cerebral prefrontal area and counseling intervention. Aromatherapy is known to be effective to improve mood. We thus evaluated the influence of counseling on the efficacy of aromatherapy in healthy young women. Participants in a room filled with the fragrance of bergamot completed both a self-reported questionnaire (motivation, feeling of drowsiness and general fatigue) and multi-dimensional fatigue inventory-20 (MFI-20). Further, as an objective measure of changes in stress, blood flow in the inferior frontal cortex was evaluated by near-infrared spectroscopy (NIRS). MFI-20 showed that the combination of aromatherapy with counseling significantly improved both brain activity and motivation, as compared to aromatherapy alone, though the self-reported questionnaire showed no significant difference. Regional blood flow in the inferior frontal cortex was significantly decreased by exposure to aromatherapy with counseling, compared to aromatherapy alone (p<0.05). The value of the NIRS-derived laterality index (LI), which is considered to be a measure of stress, was decreased by aromatherapy with counseling. Thus, we confirmed that the combination of aromatherapy with counseling intervention significantly improved mood and stress. Our results also demonstrated that counseling intervention increased the effectiveness of aromatherapy.
プラセボ効果は薬の効果に対する期待と過去に薬が効いたという条件付けが働くことに基づく効果であり、脳の認知機能を司る部位に関連がある。この部位は脳の前頭前野に位置し、近赤外線分光法(NIRS)を使用することでその活性度を非侵襲的に測定できる。また最近10年で、脳内化学伝達物質の遺伝子多型でプラセボレスポンダーとノンレスポンダーを区別するプラセボーム研究が台頭している。本研究では、脳内化学伝達物質の中でも5-hydroxitryptamine transporter ( 5-HTT ) 、Catechol-O-methyltransferase ( COMT )の遺伝子多型に注目し、プラセボ効果との関連性を検討することを目的としている。主観的指標として Stanford Sleepiness Scale( SSS )と Visual Analog Scale ( VAS )による眠気度調査を行い、客観的指標として近赤外分光法( NIRS )による脳血流量変化を測定した。また、5-HTT遺伝子多型 ( L/L、S/L、S/S ) とCOMT 遺伝子多型( Val/Val、Val/Met、Met/Met )を行なった。プラセボ投与前に比べ投与後で SSS と VAS ともに有意に眠気が改善された。NIRS では、認知を司る部位の脳血流量が投与後で有意に増加した。SSSとVASではVal/Met 群の方が Val/Val 群より大きな眠気改善傾向が見られた。またNIRS左脳での脳血流量は Met/Met 群が Val/Val 群と比較して増加傾向が見られた。有意差は見られないものの、Metアレルは Val アレルよりもプラセボ効果との強い関連性が示唆された。この結果は、78th FIP World Congress of Pharmacy and Pharmaceutical Sciences(英国・Glasgow、2018年9月)にて学会発表した。