I don't think it encourages it, or tells you not to. It shows how drugs can change your perception and bring you back to your 'childish' mind through joy, experiences, etc. but in the end you cannot replace your mind as a child permanently. Drugs aren't even that relevant in the film, they are just used as a means to bring across the point that no matter what you try (drugs, or anything else in life for that matter), you cannot achieve the same childish mind you once had and desire to still have. The goggles they wear aren't necessariliy based on drugs, but rather used as a shield to screen reality. Reality is depressing.