Meditation is sometimes used as a cure all ... a panacea of ills.
The truth is that meditation and drugs don't mix.
If one was using drugs or drink alcohol then decides to use meditation .. (shrugs shoulders)
It really doesn't make meditation a gateway device for drug and alcohol abuse. (or vicesa versa).
There is no relationship other than the one people want to perceive.
The meditation which is a universal panacea can be done under any state of mind whatsoever because it has no limitations. However, the most skillful approach for most individuals is to not mix meditation with drugs, but it is not a universal truth of any kind.
Meditation can only be done with a proper mind set. Not any state of mind will do.
For example, a psychotic state of mind will not focus and will engage all manner of thoughts as real whether it is or not.
No calming of mind, no concentration, no benefit.
An example of a drug not working well with meditation is heroin. The state of mind induced by the drug is one of stupor and mental weakness.
No benefit will come from practice under those conditions ... if practice is even possible.
Meditation does have limit because it is an expedient method given to those who have the chance to benefit from its practice.
It isn't a cure all. In the simplest of stages, it is a method of feedback to help produce a state of calm, equanimity, mindfulness, awareness.
One can't use the feedback system if the proper mind set is not there to start with.
Some may point out that a paranoid state of mind can be coaxed into meditation.
Well, the mind must be brought into a more calm and natural state become meditation practice can occur.
A person must be talked down and brought to a state of mind where it can begin the process.