Use of opium for pain control dates back to ancient times. When consumed, this narcotic drug enters the bloodstream and quickly attaches to proteins called opioid receptors on nerve cells in the brain, spinal cord, and other parts of the body. This process blocks pain sensations from the body, in part by stimulating the release of dopamine within the brain. Although very eff ective as pain suppressors, opioid drugs can be highly addictive, especially if they are used over a long period of time. They often have the undesired eff ect of convincing the brain that for contented survival higher and higher doses are needed daily. This evolutionary dependency is classically defi ned as an addiction.