Look at this quote:

"Now-a-days several individuals use hallucinogens for a wrong notion that they promote spiritual growth, sharpen perception, help in personallity development and open up reality."

We see the phrase 'wrong notion'.
The wrong notion is a notion of opinion and we can see that this notion or opinion is wrong in the opinion of the person who wrote it. It is not a factual statement its a stament of opinion.