There is an article in todays “Telegram” about a British study that concludes that heavy pot smoking leads to schizophrenia when the smokers are in their 40’s and 50’s.
Did that study rule out the possibility that in one's 40s and 50s schizophrenia leads to heavy pot smoking?
And even if the alleged causal link exists, what should we conclude from that? It's also true that heavy use of the drug alcohol at any age leads to negative mental and physical health effects.