Apps that could help people overcome their worst fears have been developed for smartphones.

One app claims to help people who are scared of spiders, using a technique called systematic desensitisation.

Users have to play video games that feature cartoon spiders which look cute and harmless.

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At first the spiders are cute and not very scary

As the game progresses, the spiders start to look more realistic. Eventually players have to help an injured tarantula.

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The spiders slowly become more realistic

The game was developed by two mental health experts.

However some experts have warned that apps should not be seen as a replacement for seeing a doctor.

Unusual phobias

About 10% of people have a phobia. We can be afraid of just about anything.

Arachnophobia - fear of spiders

Claustrophobia - fear of being trapped in a small space

Turophobia - fear of cheese

Coulrophobia - fear of clowns

Omphalophobia - fear of belly buttons

Triskaidekaphobia - fear of the number thirteen

Paraskevidekatriaphobia - fear of Why is fear of Friday 13th unlucky?

Globophobia - fear of balloons