A well known blood pressure drug can completely cure phobias and post traumatic stress , researchers said.
Merel Kindt and her colleagues at the University of Amsterdam, the Netherlands, have revealed that this drug is called the beta blocker propranolol.
The researcher points out that people who experienced traumatic events-like rape and car crashes-showed fewer signs of stress while recalling the event when they had been injected with the beta blocker propranolol in experiments conducted in the past.
However, it still remained unclear whether the effect would be permanent or not because fearful memories often return, even after people have been treated for them.
Merel said that her team investigated whether propranolol could stop fear returning in the longer term by conditioning 60 healthy students to associate a picture of a spider with an electric shock, so that they would eventually be startled by the picture even in the absence of a shock.
The researchers noted that the startle response was eliminated in students who were given oral propranolol before seeing the picture.
They even observed that the response did not return when the students were put through a second round of conditioning, which should have reinstated their fear.
Merel said that that observation indicated that the link between the students' memories and fears might have been permanently broken.
She further said that those given a placebo pill could eventually be trained not to be startled by the spider picture, by repeatedly showing it to them in the absence of a shock.
Experiencing traumatic events causes the body to release adrenaline, which affects ahe brain area involved in emotional processing called the amygdala, and makes an emotional connection to the memory.
Merel points out that reliving the memory triggers further release of adrenaline, reinforcing the memory still further.
Given that propranolol blocks adrenaline receptors in the amygdala, she thinks that it may also block this reinforcement process and break fear association.
''We can't prove that the memory has gone away, but it is at least weakened so much that we can't find it anymore,'' New Scientist magazine quoted her as saying.
University College London memory expert Chris Brewin calls the findings interesting, but warns that Merel's team only tested the volunteers over the course of three days.
''The fear might come back if they tested them several weeks later,'' he says.
He also pointed out that he research team only looked at the degree to which the volunteers were startled, but conditions like post traumatic stress disorder often involve other emotions such as anger and shame, and it had yet to be found how propranolol would affect them.
A research article on the study has been published in the journal Nature Neuroscience.