How do antagonists cause precipitated withdrawals?

The antagonist brings on opiate withdrawal symptoms all at once instead of it leaving your body gradually over a period of days/weeks depending on how long and how much they've been using. Antagonists are drugs that bind to the receptors, but don't stimulate them like agonists do. Antagonists can prevent or reverse the action of dopamine by keeping it from attaching to receptors. They help regulate the system by kind of "turning down" dopamine activity. The withdrawal symptoms are due to an addict having been taking artificial dopamine (the opiate), and the body stops producing its own. When the addict stops taking the drug, it takes a while for the body to begin to start producing dopamine on an acceptable level again. So, taking the antagonist, it stops the dopamine action at once, instead of it leaving the body gradually.