Even higher level of astral and also mental dimension are very hard to change. Yes, if you are not disciplined enough, your subconscious mind can slip a bits of imagination into your OBE. Generally, lucid dream is just dream with added lucidity. Your consciousness, your senses... everything is from less clear to as normal as in real life. But when you do OBE... The higher dimension(or level of particular dimension) you experience the stronger consciousness seems to be. When I was in budhic dimension, then everything seemed to be uncontrollable. I wasn't even able to move in my surrounding at the start. It was so very different in comparison to mental dimension which is again more difficult than astral one.
I'm not sure about drug induced experiences... In my opinion they have not the quality of common OBE. You do something to your consciousness but your consciousness is not ready for going out.