THE JOURNAL OF ALTERNATIVE AND COMPLEMENTARY MEDICINE Volume 18,Number 8,2012,pp.798-804 Mary Ann Liebert.Inc. D0:10.1089/acm.2011.0551 Effect of Sweet Orange Aroma on Experimental Anxiety in Humans Tiago Costa Goes,MSc,Fabricio Dias Antunes,MD, Pericles Barreto Alves,PhD,and Flavia Teixeira-Silva,PhD' Abstract Objectives:The objective of this study was to evaluate the potential anxiolytic effect of sweet orange(Citrus sinensis)aroma in healthy volunteers submitted to an anxiogenic situation. Design:Forty (40)male volunteers were allocated to five different groups for the inhalation of sweet orange essential oil (test aroma:2.5,5,or 10 drops),tea tree essential oil (control aroma:2.5 drops),or water (non- aromatic control:2.5 drops).Immediately after inhalation,each volunteer was submitted to a model of anxiety, the video-monitored version of the Stroop Color-Word Test(SCWT). Outcome measures:Psychologic parameters(state-anxiety,subjective tension,tranquilization,and sedation)and physiologic parameters (heart rate and gastrocnemius electromyogram)were evaluated before the inhalation period and before,during,and after the SCWT. Results:Unlike the control groups,the individuals exposed to the test aroma(2.5 and 10 drops)presented a lack of significant alterations(p>0.05)in state-anxiety,subjective tension and tranquillity levels throughout the anxiogenic situation,revealing an anxiolytic activity of sweet orange essential oil.Physiologic alterations along the test were not prevented in any treatment group,as has previously been observed for diazepam. Conclusions:Although more studies are needed to find out the clinical relevance of aromatherapy for anxiety disorders,the present results indicate an acute anxiolytic activity of sweet orange aroma,giving some scientific support to its use as a tranquilizer by aromatherapists. Introduction the other hand,this therapy still does not have much scien- tific support.6.7 chatne diornders in the neral ppulon Double-blind,randomized,placebo-controlled clinical trials performed to evaluate the effect of essential oils on their treatment is still challenging,as the drugs used for the anxiety symptoms are gradually starting to appear in the relief of anxiety symptoms can have important side-effects, literature (for a systematic review,see Cooke and Ernst). promote therapeutic dependence,or present a delay in their However,in most of these studies,exposure to the essential onset of action.Furthermore,not all patients benefit from the oil odor was accompanied by massage.This makes it difficult available treatments,and only a few of them have a response to draw firm conclusions about the essential oil effect,as the near complete recovery.3 massage per se is able to reduce anxiety scores.s However,in These facts justify the growing search for alternative or a recent study performed with rats,animals submitted to complementary procedures for the relief of anxiety symp- two different experimental models of anxiety,after being toms.Among these procedures,one can find aromatherapy, exposed to Citrus sinensis aroma,showed less anxiety than which is the use of essential oils as an alternative treatment animals exposed to air only.This result could not be at- for medical purposes.4 tributed to massage,previous experience with the aroma, According to Charlesworth,5 about 60%of health com- therapeutic relationship,or even to an unspecific effect of plaints in the medical office are stress-related,and aro-any aroma,as animals exposed to Melaleuca alternifolia es- matherapy could be a great alterative to conventional sential oil did not behave differently from control animals. medication since it has shown positive emotional effects.On Thus,the probability of C.sinensis essential oil having a "Departamento de Fisiologia,Centro de Ciencias Biologicas e da Saude,Universidade Federal de Sergipe,Sergipe,Brazil. 2Departamento de Quimica,Centro de Ciencias Exatas e Tecnologicas,Universidade Federal de Sergipe,Sergipe,Brazil. 798Effect of Sweet Orange Aroma on Experimental Anxiety in Humans Tiago Costa Goes, MSc,1 Fabrı´cio Dias Antunes, MD,1 Pe´ ricles Barreto Alves, PhD,2 and Flavia Teixeira-Silva, PhD1 Abstract Objectives: The objective of this study was to evaluate the potential anxiolytic effect of sweet orange (Citrus sinensis) aroma in healthy volunteers submitted to an anxiogenic situation. Design: Forty (40) male volunteers were allocated to five different groups for the inhalation of sweet orange essential oil (test aroma: 2.5, 5, or 10 drops), tea tree essential oil (control aroma: 2.5 drops), or water (non￾aromatic control: 2.5 drops). Immediately after inhalation, each volunteer was submitted to a model of anxiety, the video-monitored version of the Stroop Color-Word Test (SCWT). Outcome measures: Psychologic parameters (state-anxiety, subjective tension, tranquilization, and sedation) and physiologic parameters (heart rate and gastrocnemius electromyogram) were evaluated before the inhalation period and before, during, and after the SCWT. Results: Unlike the control groups, the individuals exposed to the test aroma (2.5 and 10 drops) presented a lack of significant alterations ( p > 0.05) in state-anxiety, subjective tension and tranquillity levels throughout the anxiogenic situation, revealing an anxiolytic activity of sweet orange essential oil. Physiologic alterations along the test were not prevented in any treatment group, as has previously been observed for diazepam. Conclusions: Although more studies are needed to find out the clinical relevance of aromatherapy for anxiety disorders, the present results indicate an acute anxiolytic activity of sweet orange aroma, giving some scientific support to its use as a tranquilizer by aromatherapists. Introduction Anxiety disorders are the most prevalent class of psy￾chiatric disorders in the general population.1 However, their treatment is still challenging, as the drugs used for the relief of anxiety symptoms can have important side-effects, promote therapeutic dependence, or present a delay in their onset of action.2 Furthermore, not all patients benefit from the available treatments, and only a few of them have a response near complete recovery.3 These facts justify the growing search for alternative or complementary procedures for the relief of anxiety symp￾toms. Among these procedures, one can find aromatherapy, which is the use of essential oils as an alternative treatment for medical purposes.4 According to Charlesworth,5 about 60% of health com￾plaints in the medical office are stress-related, and aro￾matherapy could be a great alternative to conventional medication since it has shown positive emotional effects. On the other hand, this therapy still does not have much scien￾tific support.6,7 Double-blind, randomized, placebo-controlled clinical trials performed to evaluate the effect of essential oils on anxiety symptoms are gradually starting to appear in the literature (for a systematic review, see Cooke and Ernst6 ). However, in most of these studies, exposure to the essential oil odor was accompanied by massage. This makes it difficult to draw firm conclusions about the essential oil effect, as the massage per se is able to reduce anxiety scores.8 However, in a recent study performed with rats, animals submitted to two different experimental models of anxiety, after being exposed to Citrus sinensis aroma, showed less anxiety than animals exposed to air only.9 This result could not be at￾tributed to massage, previous experience with the aroma, therapeutic relationship, or even to an unspecific effect of any aroma, as animals exposed to Melaleuca alternifolia es￾sential oil did not behave differently from control animals. Thus, the probability of C. sinensis essential oil having a 1 Departamento de Fisiologia, Centro de Cieˆncias Biolo´gicas e da Sau´de, Universidade Federal de Sergipe, Sergipe, Brazil. 2 Departamento de Quı´mica, Centro de Cieˆncias Exatas e Tecnolo´gicas, Universidade Federal de Sergipe, Sergipe, Brazil. THE JOURNAL OF ALTERNATIVE AND COMPLEMENTARY MEDICINE Volume 18, Number 8, 2012, pp. 798–804 ª Mary Ann Liebert, Inc. DOI: 10.1089/acm.2011.0551 798