The use of cannabis has led to a dramatic 85% rise in hospital admissions of people suffering with mental health problems.
Cannabis is the most widely used illegal drug with 2m regular users.In a decade the number of admissions linked to the drug has soared to nearly 1000 a 63% rise in the in the last five years alone.
In 1996/97 there were 510 admissions to hospital of people suffering from mental health problems due to the use of the drug. In 2005/06 that number has risen to 946.
Marjorie Wallace, chief executive of the mental health charity Sane said: "Sane has been saying for years that there is a link between psychosis and cannabis, particularly in its more potent forms, so this increase in hospital admissions comes as no surprise.
"We strongly urge the Government to heed the growing evidence and take urgent action to warn young people that some of them are risking lifelong mental illness, that they are playing Russian roulette with their minds."
And almost half of those patients treated for a mental health problem go on to develop a schizophrenic illness the Danish study, which can be found in the British Journal of Psychiatry has suggested.
There are an estimated 1,500 new cases of cannabis related schizophrenia per year with the drug contributing as the cause of 10% of all cases.
Professor Robin Murray, professor of psychiatry at London's Institute of Psychiatrists, said: "There is no doubt that cannabis related psychiatric problems have increased sunstantially.
"This might be down to better recognition, but I would say these figures are just the tip of the iceberg. Its only more recently that psychiatrists have understood the importance of cannabis use."