http://news.bbc.co.uk/1/hi/health/4218851.stmCannabis mental health risk probe
Cannabis was reclassified so police could target harder drugs
The government says it will review all academic and clinical studies linking cannabis use to mental health problems.
The Department of Health says it is now generally agreed among doctors that cannabis is an "important causal factor" in mental illness.
It follows a mental health group's call for the government to investigate "the link between cannabis and psychosis".
Rethink said its reclassification from a Class B to Class C drug sent a "confusing message" to young people.
The charity wants the Commons Health Select Committee to launch an inquiry into the effect cannabis has on users.
Its call was also backed by health campaign group Sane which wants the classification of cannabis to be reversed.
A Department of Health spokesman said it was already commissioning a review.
"We have no objection to the health select committee looking into this," he said.
'Common consensus'
"However we are in the process of commissioning an expert review of all the academic and clinical evidence of the link between cannabis use and mental health, particularly schizophrenia.
"There is medical clinical evidence now that there is an important causal factor between cannabis use and schizophrenia - not the only factor, but an important causal factor. That is the common consensus among the medical fraternity."
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