"Mental illness soars in UK's skunk hotspots"

Screams the headline in The Independent, continuing breathlessly,

"Some areas have suffered a tenfold increase in people mentally ill from using the drug. Nationally, skunk smokers are ending up ill in hospital in record numbers, with admissions soaring 73 per cent."

Shock! Horror! Dismay! Anguish! It then continues on a more sobre note:

"The number of adults recorded as suffering mental illness as a result of cannabis use has risen sharply from 430 in 1996 to 743 in 2006."

Wot? 743? Out of an estimated two million regular users?

That means that about one-in-three thousand regular cannabis users goes mad each year, considerably better odds than I guesstimated here, using pessimistic assumptions. The link between cannabis and mental illness is fairly tenuous anyway, see Leslie Iverson's summary halfway down this.

Further, are they distinguishing between 'cannabis' and 'skunk'? Not clear to me. Maybe all these admission are due to people smoking skunk, in which case cannabis is totally harmless.