A new television campaign warning teenagers of the dangers of smoking cannabis has been launched.
The advert sees youngsters replacing their damaged brain by buying another one in a shop, set in the future.
An empty store in London's Shepherd's Bush was converted into a "brain shop", complete with a fitting room and surgical instruments.
More than 20 different "brains" and assorted "spare parts" (including cerebral fluid and memory stalks) are on offer, each relating to a different symptom cannabis can produce, such as mood swings, paranoia, being sick and lack of motivation.
It has been produced by Frank, a national drugs information service run by by the Department of Health, the Home Office and the Department for Education and Skills.
The service pointed to increasing evidence of a link between cannabis and mental health problems such as schizophrenia.
A spokesman said: "It's important that young people know the risks about cannabis.
"It's the illegal drug they are most likely to come across, and some people mistakenly think it is harmless.
"Cannabis can increase the risk of mental health problems in some, especially if these things run in the family.
"With stronger strains of cannabis than ever before, there's even more reason to get clued up."
