OP do you mean genuine prescriptions, or do you mean black market prescription drugs and research chemicals?
The former isn't any more problematic than going to the GP. The latter is a big problem, albeit nothing new - just less visible than it used to be when things were sold on the street.
I have sadly worked with a fair few individuals who caused themselves serious damage using research chemicals that had hallucinogenic effects - long term repeat exposure to god knows what. I also worked with someone who tried to convince me that their 400 pills of etizolam (bought on dark web) wasn't a problem - for comparison, it's at least 5x stronger than diazepam!