The olfactory glands are physically close to parts of the brain that store memories and process emotions. "The amygdala, in particular, plays an important role both in the long-term, unconscious storage of memories of fear and in the emotional processing of olfactory stimuli" (Otto, 2000).
This is why, I suppose, that whenever I smell rubber my stomach churns and I'm immediately alert to the possibility of danger, having first and seriously smelt rubber in the gas mask that often covered my face as a child during the Blitz of London by the Nazis.
The reverse procedure -- using pleasant scents to anchor calm and relaxation in the face of intrusive, upsetting emotions -- was used unwittingly by me and deliberately by other hypnotherapists.
After researchers used this powerful effect of the sense of smell to mitigate phobias, panic disorder and a single, though dramatic, case of combat-induced PTSD [Abramowitz, E., & Lichtenberg, P., 2009] they decided to test whether other combat veterans could benefit from HOC.
They found that 36 soldiers (some on active duty and others discharged) experienced significant relief (up to a year later) with HOC from their PTSD with its characteristic nightmares, flashbacks, anxiety and terror. All of the soldiers had not previously improved with traditional techniques.
To counter the PTSD triggers (e.g. the smell of diesel fumes or burning flesh) one of 3 aromatic oils -- vanilla, red mandarin or basil) was used to associate the scent with sense of control and calm. [Abramowitz and Lichtenberg, 2010].
Each of 6 sessions lasted one and a half hours.
- First, an olfactory history clarified what smells the soldiers set off unpleasant memories. Then the soldier was taught to associate his (all the subjects were men -- it remains to be seen whether female soldiers will fare as well with HOC) selected aromatic oil with pleasant memories and a sense of control and calm.
- In the second session the soldier, after an hypnotic induction, was encouraged to recall past experiences in which he was stressed but functioned well. Post-hypnotic suggestions were offered to deal successfully with flashbacks to horrific traumatic events.
- Together the therapist and the patient construct an imaginary but highly detailed "safe place." While hypnotized, the soldier repeatedly goes in his mind to this safe place while at the same time inhaling his chosen aromatic oil. (Thus conditioning him to associate feeling safe and calm with the smell).
- In the 4th and 5th sessions the patient -- in hypnosis and smelling the pleasant scent -- is encouraged to remember the trauma, especially the smells. The therapist reframes the experience over and over, replacing the olfactory content of the traumatic memory with the pleasant scent.
- In session 6 the soldier practices what he has learned. Furthermore, he is taught to carry the vial of aromatic oil with him as a tool to combat anxiety or panic attacks in relevant situations.
During the HOC experiment medications were continued. Since the same psychiatrist administered both drugs and hypnotherapy, he modified the meds as required after the research.
Abramowitz., E. (2003, May). "Scent bridge" and scent conditioning in hypnotherapy of chronic combat PTSD patients. Presented at the Annual Congress of the Israel Society of Hypnosis, Tel Aviv, Israel.
Abramowitz, E., and Lichtenberg, P., (2009). Hypnotherapeutic olfactory conditioning (HOC): Case studies of needle phobia, panic disorder, and combat-induced PTSD. International Journal of Clinical and Experimental Hypnosis, 57: 184-197
Abramowitz, Eitan G., and Lichtenberg, Pesach (2010). A New Hypnotique Technique for Treating Combat-Related Posttraumatic Stress Disorder: A Prospective Open Study. International Journal of Clinical and Experimental Hypnosis, 58(3): 316-328.
Chu, S. & Downes, J.J. (2002). Proust nose best: Odors are better cues of autobiographical memory. Memory and Cognition, 30, 511-518.
Kline, N.A. & Rausch, J.L. (1985). Olfactory precipitants of flashbacks in posttraumatic stress disorder. Case reports. Journal of Clinical Psychiatry, 46, 383-384.
Otto, T., Cousens, G., & Herzog, C. (2000). Behavioral and neuropsychological foundations of olfactory fear conditioning. Behavioral and Brain Research, 110, 119-128.