Researchers at Basel University in Switzerland have carried out the study and found that giving a tablet of stress hormone cortisol can help people cure themselves of acrophobia -- a fear of high places.
The hormone, which is part of the body's "fight or flight" reaction to danger, appears to open the brain up to being reprogrammed and to permanently remove anxieties, 'The Daily Telegraph' reported.
Tests on 40 patients with acrophobia found those given cortisol in combination with behavioural therapy dramatically reduced their aversion.
The researchers said their findings, published in the 'Proceedings of the National Academy of Sciences' journal, could lead to the development of effective treatments for a host of anxiety disorders.
Half the participants were given the drug and the others a placebo an hour before being subjected to a virtual- reality outdoor elevator ride.
Their fear was measured three to five days and one month after the last exposure session through an established acrophobia questionnaire and by sensors that picked up their sweat known as skin conductance examinations.
Compared with those given the dummy pill participants who took cortisol suffered significantly less anxiety and a smaller increase in skin conductance during follow-up. The effect also lasted longer and still apparent a month later. Lead researcher Dr Dominique De Quervain said this suggests cortisol can enhance "exposure therapy" to reduce fear of heights. This involves repeated, controlled, exposures to fearful situations that gradually dampens their fright.
The researchers said: "Adding cortisol to exposure therapy resulted in a significantly greater reduction in fear of heights as measured with the acrophobia questionnaire both at post-treatment and at follow-up, compared with placebo.
"Furthermore, subjects receiving cortisol showed a significantly greater reduction in acute anxiety during virtual exposure to a phobic situation at post-treatment and a significantly smaller exposure-induced increase in skin conductance level at follow-up.
"The present findings indicate that the administration of cortisol can enhance extinction-based psychotherapy."
They said the results add further evidence to research showing fear can be controlled by drugs and such studies may contribute "to the development of novel therapeutic strategies to treat anxiety disorders."