How Does Heroin Work?
Heroin is either injected, snorted, or smoked. It travels rapidly through the bloodstream to the brain, where it acts on opiate receptors (proteins that are activated specifically by opiate drugs). These receptors are located throughout the brain and brainstem, but tend to be concentrated in areas responsible for pain sensation, reward, and basic central nervous system functions such as breathing and blood pressure. These actions make it not only highly rewarding, but highly lethal as well, as it can cause breathing to completely stop.
How Does it Cause Addiction?
Regular heroin use also causes tolerance and dependence, which result in physical addiction. Tolerance is defined by the National Institute on Drug Abuse (NIDA) as when “more of the drug is needed to achieve the same intensity of effect.” Dependence is defined as “the need to continue use of the drug to avoid withdrawal symptoms.” These states essentially mean that the more heroin someone uses, and the more frequently they use, the more of the drug that they need to simply feel “OK”. The body (and brain) get used to receiving the heroin on a regular basis; therefore, the “normal functioning” levels of many brain areas become dependent on it. When use stops suddenly, the body and brain can’t adjust immediately, which brings on the severe withdrawal symptoms that are well-known by heroin addicts. Many long-term heroin users report that they don’t even get high anymore, but they have to keep using to ward off sickness and other painful withdrawal symptoms. NIDA also cites research showing that prolonged heroin use kills off the white matter in the brain, “which may affect decision-making abilities, the ability to regulate behavior, and responses to stressful situations.”