Miranda Hitti

March 30, 2006 -- The hormone cortisol may help defuse phobias, new research shows.

A phobia is a persistent, excessive fear of a specific object or situation. Scientists recently studied two small groups of people with phobias. One group feared public speaking; the others were extremely afraid of spiders.

Participants faced their fears in the experiment. They were less fearful if they had taken the corticosteroids cortisol or cortisone an hour earlier.

Those steroids may make it harder to recall fearful memories, thus helping to calm phobias, write Leila Soravia, DrPhil, and colleagues.

Soravia works at the Institute of Psychology at Switzerland's University of Zurich. Her study appears in Proceedings of the National Academy of Sciences.

Public Speaking Phobia

Twenty-one participants feared public speaking. Nine took a dose of cortisone by mouth. The others took a placebo treatment containing no cortisone.

An hour later, participants were given 10 minutes' notice to prepare a speech pitching themselves for a job. They were also told that after the speech, they would take a mental math test in front of an audience.

Participants wore heart rate monitors and self-rated their fear. After hearing about the speech and math test, heart rates jumped up for the placebo group but only increased slightly for the cortisone group. The cortisone group also reported less fear than the placebo group, the study shows.

Slaying Spider Fears

The spider test included 20 people with spider phobias. Half got oral cortisol; half got a placebo.

An hour after treatment, participants were shown a color photo of a large black spider with long legs. The photo included a ruler showing that the spider's longest legs spanned nearly four inches.

Participants rated their fear and desire to get away from the photo. They saw the photo six times. For comparison, no one got cortisol in the first and last sessions.

Fear fell for the cortisol group with each session. Those benefits remained in the last session -- held two days after cortisol treatment stopped. The placebo group didn't make as much progress in taming its phobias.

Cortisol and cortisone showed "potentially beneficial effects in phobia" but didn't seem to calm general anxiety unrelated to phobias, Soravia's team writes.

Steroids aren't typically used to treat phobias or anxiety. They can have side effects including osteoporosis (thinning of bones) and diabetes, especially with long-term use.

SOURCES: Soravia, L. Proceedings of the National Academy of Sciences, April 4, 2006; vol 103: pp 5585-5590. News release, Proceedings of the National Academy of Sciences.

Reviewed by Louise Chang