Studies on aromatherapy have examined a variety of other conditions: sedation and arousal;[11,12] startle reflex and reaction time;[13,14]psychological states such as mood, anxiety, and general sense of well-being;[15,16,17,18,19,20,21,22,23,24,25,26,27,28,29] psychiatric disorders;neurologic impairment;chronic renal failure;agitation in patients with dementia;[31,32,33,34,35] smoking withdrawal symptoms;[36,37] motion sickness;postoperative nausea;[39,40] nausea and emesis in combination with fatigue, pain, and anxiety in patients in labor;[25,26,41] pain alone;[42,43,44,45] and pain in combination with other symptoms.[22,23,25,26]
Published articles have described the use of aromatherapy in specific hospital settings such as cancer wards, hospices, and other areas where patients are critically ill and require palliative care for pain, nausea, lymphedema,[46,47] generalized stress, anxiety, and depression. These observational studies provide examples of the clinical uses of aromatherapy (and other CAM modalities), though they are generally not evidence-based. Subjects have included hospitalized children with HIV, homebound patients with terminal disease, and hospitalized patients with leukemia. Aromatherapy has also been used to reduce malodor of necrotic ulcers in cancer patients.
Studies of aromatherapy use with mental health patients have also been conducted. Most of the resulting articles describe successful incorporation of aromatherapy into the treatment of these patients, though outcomes are clearly subjective.
Theories about the mechanism of action of aromatherapy and essential oils differ, depending on the community studying them. Proponents of aromatherapy often cite the connection between olfaction and the limbic system in the brain as the basis for the effects of aromatherapy on mood and emotions; less is said about proposed mechanisms for its effects on other parts of the body. Most of the aromatherapy literature, however, lacks in-depth neurophysiological studies on the nature of olfaction and its link to the limbic system, and it generally does not cite research that shows these links. Proponents of aromatherapy also believe that the effects of the treatments are based on the special nature of the essential oils used and that essential oils produce effects on the body that are greater than the sum of the individual chemical components of the scents.
These assertions have been contested by the biochemistry and psychology communities, which take a different view of the possible mechanism of action of odors on the human brain (most do not differentiate the odors produced by essential oils from those of synthetic fragrances). This neurobiological view, which focuses mostly on the emotional and psychological effects of fragrances (as opposed to the other symptomatic effects claimed by aromatherapists), takes into account what is known about olfactory transduction and the connection of the olfactory system to other central nervous system functions, including memory; however, it is primarily theoretical because of the lack of significant research addressing this topic.
- Tisserand R: Essential oils as psychotherapeutic agents. In: Van Toller S, Dodd GH, eds.: Perfumery: The Psychology and Biology of Fragrance. New York, NY: Chapman and Hall, 1988, pp 167-80.
- Gattefosse RM: Gattefosse's Aromatherapy. Essex, England:CW Daniel, 1993.
- Valnet J: The Practice of Aromatherapy: A Classic Compendium of Plant Medicines & Their Healing Properties. Rochester, NY: Healing Arts Press, 1990.
- Hartman D, Coetzee JC: Two US practitioners' experience of using essential oils for wound care. J Wound Care 11 (8): 317-20, 2002.
- Asquith S: The use of aromatherapy in wound care. J Wound Care 8 (6): 318-20, 1999.
- Edwards-Jones V, Buck R, Shawcross SG, et al.: The effect of essential oils on methicillin-resistant Staphylococcus aureus using a dressing model. Burns 30 (8): 772-7, 2004.
- Hay IC, Jamieson M, Ormerod AD: Randomized trial of aromatherapy. Successful treatment for alopecia areata. Arch Dermatol 134 (11): 1349-52, 1998.
- Anderson C, Lis-Balchin M, Kirk-Smith M: Evaluation of massage with essential oils on childhood atopic eczema. Phytother Res 14 (6): 452-6, 2000.
- Ro YJ, Ha HC, Kim CG, et al.: The effects of aromatherapy on pruritus in patients undergoing hemodialysis. Dermatol Nurs 14 (4): 231-4, 237-8, 256; quiz 239, 2002.
- Cohen BM, Dressler WE: Acute aromatics inhalation modifies the airways. Effects of the common cold. Respiration 43 (4): 285-93, 1982.
- Diego MA, Jones NA, Field T, et al.: Aromatherapy positively affects mood, EEG patterns of alertness and math computations. Int J Neurosci 96 (3-4): 217-24, 1998.
- Motomura N, Sakurai A, Yotsuya Y: Reduction of mental stress with lavender odorant. Percept Mot Skills 93 (3): 713-8, 2001.
- Miltner W, Matjak M, Braun C, et al.: Emotional qualities of odors and their influence on the startle reflex in humans. Psychophysiology 31 (1): 107-10, 1994.
- Millot JL, Brand G, Morand N: Effects of ambient odors on reaction time in humans. Neurosci Lett 322 (2): 79-82, 2002.
- Stevenson C: Measuring the effects of aromatherapy. Nurs Times 88 (41): 62-3, 1992 Oct 7-13.
- Dunn C, Sleep J, Collett D: Sensing an improvement: an experimental study to evaluate the use of aromatherapy, massage and periods of rest in an intensive care unit. J Adv Nurs 21 (1): 34-40, 1995.
- Buckle J: Aromatherapy. Nurs Times 89 (20): 32-5, 1993 May 19-25.
- Hadfield N: The role of aromatherapy massage in reducing anxiety in patients with malignant brain tumours. Int J Palliat Nurs 7 (6): 279-85, 2001.
- Wilkinson S: Aromatherapy and massage in palliative care. Int J Palliat Nurs 1 (1): 21-30, 1995.
- Wilkinson S, Aldridge J, Salmon I, et al.: An evaluation of aromatherapy massage in palliative care. Palliat Med 13 (5): 409-17, 1999.
- Corner J, Cawler N, Hildebrand S: An evaluation of the use of massage and essential oils on the wellbeing of cancer patients. Int J Palliat Nurs 1 (2): 67-73, 1995.
- Louis M, Kowalski SD: Use of aromatherapy with hospice patients to decrease pain, anxiety, and depression and to promote an increased sense of well-being. Am J Hosp Palliat Care 19 (6): 381-6, 2002 Nov-Dec.
- Walsh E, Wilson C: Complementary therapies in long-stay neurology in-patient settings. Nurs Stand 13 (32): 32-5, 1999 Apr 28-May 4.
- Itai T, Amayasu H, Kuribayashi M, et al.: Psychological effects of aromatherapy on chronic hemodialysis patients. Psychiatry Clin Neurosci 54 (4): 393-7, 2000.
- Burns E, Blamey C: Complementary medicine. Using aromatherapy in childbirth. Nurs Times 90 (9): 54-60, 1994 Mar 2-8.
- Burns EE, Blamey C, Ersser SJ, et al.: An investigation into the use of aromatherapy in intrapartum midwifery practice. J Altern Complement Med 6 (2): 141-7, 2000.
- Kite SM, Maher EJ, Anderson K, et al.: Development of an aromatherapy service at a Cancer Centre. Palliat Med 12 (3): 171-80, 1998.
- Komori T, Fujiwara R, Tanida M, et al.: Effects of citrus fragrance on immune function and depressive states. Neuroimmunomodulation 2 (3): 174-80, 1995 May-Jun.
- Wiebe E: A randomized trial of aromatherapy to reduce anxiety before abortion. Eff Clin Pract 3 (4): 166-9, 2000 Jul-Aug.
- Perry N, Perry E: Aromatherapy in the management of psychiatric disorders: clinical and neuropharmacological perspectives. CNS Drugs 20 (4): 257-80, 2006.
- Ballard CG, O'Brien JT, Reichelt K, et al.: Aromatherapy as a safe and effective treatment for the management of agitation in severe dementia: the results of a double-blind, placebo-controlled trial with Melissa. J Clin Psychiatry 63 (7): 553-8, 2002.
- Smallwood J, Brown R, Coulter F, et al.: Aromatherapy and behaviour disturbances in dementia: a randomized controlled trial. Int J Geriatr Psychiatry 16 (10): 1010-3, 2001.
- Holmes C, Hopkins V, Hensford C, et al.: Lavender oil as a treatment for agitated behaviour in severe dementia: a placebo controlled study. Int J Geriatr Psychiatry 17 (4): 305-8, 2002.
- Gray SG, Clair AA: Influence of aromatherapy on medication administration to residential-care residents with dementia and behavioral challenges. Am J Alzheimers Dis Other Demen 17 (3): 169-74, 2002 May-Jun.
- Snow LA, Hovanec L, Brandt J: A controlled trial of aromatherapy for agitation in nursing home patients with dementia. J Altern Complement Med 10 (3): 431-7, 2004.
- Rose JE, Behm FM: Inhalation of vapor from black pepper extract reduces smoking withdrawal symptoms. Drug Alcohol Depend 34 (3): 225-9, 1994.
- Sayette MA, Parrott DJ: Effects of olfactory stimuli on urge reduction in smokers. Exp Clin Psychopharmacol 7 (2): 151-9, 1999.
- Post-White N, Nichols W: Randomized trial testing of QueaseEase™ essential oil for motion sickness. International Journal of Essential Oil Therapeutics 1 (4): 158-66, 2007.
- Tate S: Peppermint oil: a treatment for postoperative nausea. J Adv Nurs 26 (3): 543-9, 1997.
- Hines S, Steels E, Chang A, et al.: Aromatherapy for treatment of postoperative nausea and vomiting. Cochrane Database Syst Rev 4: CD007598, 2012.
- Oyama H, Kaneda M, Katsumata N, et al.: Using the bedside wellness system during chemotherapy decreases fatigue and emesis in cancer patients. J Med Syst 24 (3): 173-82, 2000.
- Dale A, Cornwell S: The role of lavender oil in relieving perineal discomfort following childbirth: a blind randomized clinical trial. J Adv Nurs 19 (1): 89-96, 1994.
- Göbel H, Schmidt G, Soyka D: Effect of peppermint and eucalyptus oil preparations on neurophysiological and experimental algesimetric headache parameters. Cephalalgia 14 (3): 228-34; discussion 182, 1994.
- Marchand S, Arsenault P: Odors modulate pain perception: a gender-specific effect. Physiol Behav 76 (2): 251-6, 2002.
- Kim JT, Wajda M, Cuff G, et al.: Evaluation of aromatherapy in treating postoperative pain: pilot study. Pain Pract 6 (4): 273-7, 2006.
- Barclay J, Vestey J, Lambert A, et al.: Reducing the symptoms of lymphoedema: is there a role for aromatherapy? Eur J Oncol Nurs 10 (2): 140-9, 2006.
- Kohara H, Miyauchi T, Suehiro Y, et al.: Combined modality treatment of aromatherapy, footsoak, and reflexology relieves fatigue in patients with cancer. J Palliat Med 7 (6): 791-6, 2004.
- Buckle J: Clinical Aromatherapy: Essential Oils in Practice. 2nd ed. New York, NY: Churchill Livingston, 2003.
- Wilkinson SM, Love SB, Westcombe AM, et al.: Effectiveness of aromatherapy massage in the management of anxiety and depression in patients with cancer: a multicenter randomized controlled trial. J Clin Oncol 25 (5): 532-9, 2007.
- Styles JL: The use of aromatherapy in hospitalized children with HIV disease. Complement Ther Nurs Midwifery 3 (1): 16-20, 1997.
- Rimmer L: The clinical use of aromatherapy in the reduction of stress. Home Healthc Nurse 16 (2): 123-6, 1998.
- Stringer J: Massage and aromatherapy on a leukaemia unit. Complement Ther Nurs Midwifery 6 (2): 72-6, 2000.
- Warnke PH, Sherry E, Russo PA, et al.: Antibacterial essential oils in malodorous cancer patients: clinical observations in 30 patients. Phytomedicine 13 (7): 463-7, 2006.
- Hicks G: Aromatherapy as an adjunct to care in a mental health day hospital. J Psychiatr Ment Health Nurs 5 (4): 317, 1998.