there's drugs and "drugs" and non-drugs....

drugs
are all the things that you and I take to help cure or alleviate a medically recognised condition - most are harmful if used wrongly, and most are sufficiently dangerous to have to be prescribed by a doctor. Despite the potentially ruinous effects, these drugs are generally regarded as good.
"drugs"
Then there are "drugs" - these are things that are judged as bad, perhaps because they are often used in the pursuit of fun. "drugs" also have very dangerous effects - often exaggerated by the media, they are in many cases no more dangerous than some things you can buy over the counter in any chemist's. Many of the most dangerous effects of "drugs" depend on the context in which they are taken.
Cannabis is a "drug" - and there is some evidence that long-term, heavy use can trigger schizophrenia in pre-disposed people. However it's benefits in treating conditions like multiple schlerosis, Parkinson's disease and arthritis are at least as well proven as it's ill effects. Which makes the decision of Carlisle Crown Court to prosecute and convict Lezley and Mark Gibson for supplying small quantites of cannabis to MS sufferers, utterly bizzare. Lezley herself suffers from MS and gets relief by taking cannabis, so she and her partner Mark, being kind and helpful folks supplied small amounts of cannabis to other accredited MS sufferers. They didn't charge for this service, but accepted donations to cover costs. Following their conviction they will have to stop doing this. Cannabis, in the form of Sativex spray, is available to people with MS, on prescription - but due to a cowardly government fudge, it isn't properly licenced, so the legal basis for doctor's supplying it is uncertain.
I would stake my life on cannabis being no more dangerous than at least four of the drugs I am currently taking - but because it is a "drug" it cannot be a drug - my GP cannot, for example, prescribe cannabis to relieve my arthritis.

non drugs
...I won't even mention alcohol and nicotine, which are still most peoples non-drugs of choice.

Our society has some pretty strange, inconsistent and hypocritical attitudes towards drugs/"drugs"/non-drugs ... and it's to the detriment of just about everybody except landlords, drink and fag manufacturers and dealers.