Scared of Psycho? Here's why

Scientists in Germany believe they have discovered why some people are terrified by horror films while others find them highly enjoyable.

In an article published in the journal Behavioural Neuroscience, researchers from the University of Bonn say that variants of the COMT gene affect chemicals in the brain that are associated with anxiety differently.

Those people who have two copies of a specific version were found to be more disturbed by unpleasant pictures, while those who had only one copy of the gene, plus one copy of another, were more able to keep their emotions in check.

This could be why some people were terrified by films such as The Exorcist and Psycho, while others laughed and were entertained.

The scientists also say the research could help to treat anxiety disorders.

Psychologist Christian Montag said the gene is likely to have developed when humans lived in more dangerous surroundings and were at risk from predators.

"It was an advantage to be more anxious in a dangerous environment," he remarked.

The Exorcist was released in 1973 and became one of the most profitable horror films of all time.

However, at the time of its release, many people reacted negatively to the film, with some leaving the cinema and others vomiting in the aisles.

In contrast, many people did not find the film frightening in the slightest and it has since been parodied by both the Scary Movie franchise and the Simpsons.