FAYETTEVILLE, Ark. - The sight of a bloody wound or a hypodermic needle puncturing skin can cause many people to pass out. Such a response may involve a complex interaction between fear and disgust, and understanding the interaction may help treat people who faint from such causes.

A team of University of Arkansas researchers recently presented a study showing the relation between fear, disgust and fainting. Graduate student Bunmi O. Olatunji, assistant professor Nathan Williams and professor Jeff Lohr presented the results at the Association for the Advancement of Behavior Therapy conference in New Orleans in November. The resulting paper, "Disgust, Anxiety and Fainting Symptoms Associated with Blood-Injection-Injury Fears: A Structural Model," will be published in a 2005 issue of the Journal of Anxiety Disorders.

Olatunji and his team compared two basic approaches that attempt to explain the cause of fainting. Blood-injection-injury phobia is characterized by extreme aversion to the sight of blood, injection, wounds and medically related stimuli and is uniquely characterized by the tendency to evoke fainting. One approach to explaining the fainting response proposes a direct relation between the experience of disgust and fainting in response to blood-injection-injury stimuli. This approach suggests that a high sensitivity to disgust may be a predisposing factor to fainting. The second approach suggests that a heightened fear response to the stimuli is the key variable in eliciting fainting sensations. This approach also argues that that the disgust-fainting relationship may be entirely mediated by the fear, rather than disgust functioning as a direct and independent predictor of fainting symptoms.

The team enlisted the help of 259 undergraduate students, who earned research credit for their participation. The groups consisted of 177 females and 82 males, with a median age of 21.5 years. The students completed four questionnaires designed to assess their levels of disgust, anxiety, blood-injection-injury fear and faintness symptoms. The results showed that fear does mediate the relationship between disgust and fainting. Some people, Olatunji pointed out, are disgusted by the sight of an open wound, but may not be afraid of it. It is possible that the people who are highly sensitive to disgust and also are extremely fearful of the stimuli are more prone to fainting.

Olatunji and his team wanted to take the research a step further. They have identified two distinct types of disgust - "animal reminder disgust" and "core disgust." Animal reminder disgust is triggered by stimuli that remind people of the animal origins of humans, such as inappropriate death and violations of the body envelope. Core disgust is based on a sense of offensiveness and the threat of contamination, and is triggered by rotting food or small animals. Olatunji and his colleagues found that fear continues to mediate the relationship between disgust and fainting even when considering the two dimensions of disgust separately.

"Fainting tends to be stimulus bound," Olatunji said. Thus, it is possible that is serves some evolutionary function. Olatunji created a structural model showing the relation between core disgust and fainting, and animal disgust and fainting. When the two different types of disgust were compared, the relation between core disgust and fainting was insignificant, while animal reminder disgust predicted blood-injection-injury phobia and fainting.

Blood-injection-injury fears are unique because avoiding the cause of those fears can be detrimental to a person's health.

"People become very efficient in avoiding their fears," Olatunji said. "When their fear is caused by needles or blood draws, this can keep them away from necessary medical care."

Ironically, he explained, phobias are one of the easiest psychological problems to treat ó sometimes even in just one day ó but people rarely seek clinical help for phobias.

Phobias are typically treated by exposure therapy, or encouraging patients to experience their fearful emotions. Fainting can often get in the way of this type of treatment. Olatunji hopes further study into disgust, phobias and fainting will reveal new strategies for treating fainting phobics. He also hopes broadening the scope of the research can help increase numbers of blood and organ donations.