What does a higher tolerance and dependence of a drug do?

Increased dependency and tolerance basically means you'll need more of the given drug to the the same amount of high, and if you ingest the same amount you have been you won't feel as high, because your body is getting used to/immune to it.Dependence is when you have become addicted to the drug and then have a real physical or psychological need for the drug to function. That is why when you quit you go through withdrawal and it is best not to quit cold turkey if you want to succeed.