Disgust as much a factor as fear for obsessive-compulsive patients

Fear is a factor in human behavior, but behold the power of cheese – oozing, maggot-ridden cheese. Snarling dogs and other threatening images activate distinctly different regions of the brain compared with disgusting images of roaches feeding on cheese pizza or public bathrooms no one would dare use, according to scientists at the University of Florida?s Evelyn F. and William L. McKnight Brain Institute writing in the current online issue of the journal Biological Psychiatry. In addition, UF psychiatrists have found that healthy volunteers and people with obsessive-compulsive disorders, or OCD, respond in a like manner to threatening images, but those with OCD are profoundly more affected by disgusting ones.

From University of Florida:YUCK: UF RESEARCHERS SAY DISGUST AS MUCH A FACTOR AS FEAR FOR OBSESSIVE-COMPULSIVE PATIENTS

GAINESVILLE, Fla. – Fear is a factor in human behavior, but behold the power of cheese – oozing, maggot-ridden cheese.

Snarling dogs and other threatening images activate distinctly different regions of the brain compared with disgusting images of roaches feeding on cheese pizza or public bathrooms no one would dare use, according to scientists at the University of Florida?s Evelyn F. and William L. McKnight Brain Institute writing in the current online issue of the journal Biological Psychiatry.

In addition, UF psychiatrists have found that healthy volunteers and people with obsessive-compulsive disorders, or OCD, respond in a like manner to threatening images, but those with OCD are profoundly more affected by disgusting ones.

The difference suggests that obsessive people driven to behaviors such as continual hand washing may be motivated by their extreme sensitivity to disgust and not – as commonly thought – by their fear of some horrific outcome if they were to stop.

?Disgust can be misidentified as fear,? said Dr. Wayne K. Goodman, chairman of psychiatry at UF?s College of Medicine. ?A very good example from popular culture is the show ?Fear Factor.? The show depicts common fears, such as fear of heights, but one of the more challenging aspects involves disgust. Watch the facial expressions of individuals who are asked to eat bugs or various organ meats – they don?t look like they?re afraid as much as they are disgusted, and what they?re fighting off is not fear, but the desire to vomit. I wonder if ?Fear Factor? should be relabeled ?Disgust Factor.??

Modern psychological interest in disgust started in the late 19th century with renowned evolutionist Charles Darwin, who centered it in the rejection of food. Sigmund Freud, the father of psychoanalysis, linked disgust with sex as the 20th century dawned. But since then, disgust has not gotten much due as an important emotion, Goodman said. UF researchers suspect disgust may be a component in OCD, which in a given year affects about 3.3 million people between 18 and 54 in the United States.

People with OCD often say their symptoms feel like a case of mental hiccups that won?t go away. Worries, doubts and superstitious beliefs become so excessive that people spend hours cleaning their hands to remove imagined contamination or driving around the block to check that an accident didn?t occur.

?One subset of OCD patients have symptoms that are dominated by contamination fears, as opposed to, say, excessive checking on things, such as whether the stove was turned off,? said Paul Rozin, a psychology professor at the University of Pennsylvania?s Institute of Neurological Sciences. ?So far as I know, no one has shown, other than perhaps in this study, a particular link between contamination OCD and disgust sensitivity, which one would expect.?

As the disgust factor gains credibility, it will challenge traditional views of OCD, scientists said.

?We may see a paradigm shift, saying a subgroup of OCD patients who have contamination concerns have these unwanted thoughts not because of fear or anxiety, but because of an overreaction to disgust,? said Dr. Nathan Shapira, an assistant professor of psychiatry at UF?s College of Medicine and the lead researcher on the study. ?It raises the possibility for us to look at OCD in a new way.?

Researchers compared five women and three men who had contamination-centered OCD with a matched group of healthy volunteers. Study participants observed 30 pictures from the International Affective Picture System, images compiled at UF that have been rated for their emotional impact and placed in a standardized database for use in emotional research.

Study participants watched a sequence of threatening, disgusting or neutral images, including shots of snakes baring their fangs, heaps of cigarette butts, flies on pumpkin pie and soothing sunsets. At the same time, magnetic resonance images were taken of their brains.

Typically, imaging studies involve small samples of volunteers, Goodman said. The fear response and the disgust response took place in separate areas of the brain in all of the volunteers. But the level of activation when participants viewed disgust-inducing pictures was greater for OCD patients in several regions of the brain, including the insular cortex, an area that processes unpleasant tastes and smells.

It?s too early to say whether the research may point to new ways to treat OCD, but it does add emphasis to the largely unexamined subject of disgust, scientists said.

?The findings get us to think about the role of disgust in our everyday lives,? Goodman said. ?In fact, people should take note of how many times they say they find something or someone disgusting. It reminds us that disgust is a bona fide emotion. Although it has similarities to fear, it has distinct differences.?