Smell tests may predict susceptibility to PTSD
posted Wednesday, 23 April 2008

http://www.anxietyinsights.info/smel...ty_to_ptsd.htm

A world first study of Vietnam veterans' sense of smell has revealed that an inability to identify smells indicates extreme symptoms of Post Traumatic Stress Disorder (PTSD).

Researchers from the University of Melbourne and Austin Health conducting smell tests on 31 male war veterans with PTSD, recruited from Austin Health's Veterans Psychiatry Unit.

"The worse their ability to be able to name a smell, in a smell test of over 40 'scratch and sniff' odors, the harder it is to manage their emotions," said John Dileo of the University's School of Behavioral Science, who conducted the study.

Dileo says that the difficulty Vietnam veterans suffering PTSD have in putting the name to a smell may be indicative of weakness in brain pathways related to emotional processing. He says the same areas in the frontal region of the brain that are involved in identifying smells are also involved in regulating emotion.

"This is the first study to report olfactory identification ability as a predictor of aggression and impulsivity in war veterans suffering PTSD," said Associate Professor Warrick Brewer of the ORYGEN Research Centre and the University's Department of Psychiatry, who supervised the research.

"Smell impairments have been identified in other populations where people have difficulties in thinking, feeling and behavior, such as with schizophrenia, ADHD and autism," said Assoc Prof Brewer.

John Dileo says that unlike other mental health conditions, the unique aspect of PTSD is that it occurs after an event. "We don't know if the impairment existed before going to war. If we can study smell ability before and after time spent at war, we can better understand this impairment in PTSD."

"In a practical way, if we can find that smell impairment predicts the development of PTSD, smell tests could be used as a screening tool by the Australian Defence Force for example to assess vulnerability."

Associate Professor Malcolm Hopwood of the Austin Health Veterans Psychiatry Unit says PTSD is a debilitating condition characterized by symptoms of avoidance, hyper arousal and intrusive memories.

"Some individuals with PTSD also show dramatic behavioral changes such as increased aggression, anger, impulsivity and suicidal thoughts and behavior.

"PTSD is often associated with complex associated problems including alcohol abuse, mood disorders, and persistent physical health problems making it is an extremely difficult condition to diagnose and treat.

"This is significant research which will help us to better understand brain mechanisms of PTSD and hopefully help us to improve treatment and management of the condition."

Dileo JF, Brewer WJ, Hopwood M, et al. Olfactory identification dysfunction aggression and impulsivity in war veterans with post-traumatic stress disorder Psychol Med. 2008 Apr;38(4):523-531