When heroin enters the brain, it attaches to molecules on cells known as opioid receptors. These receptors are located in many areas of the brain and body, especially areas involved in the perception of pain and pleasure, as well as a part of the brain that regulates breathing.
Short-term effects of heroin include a rush of good feelings and clouded thinking. These effects can last for a few hours, and during this time people feel drowsy, and their heart rate and breathing slow down. When the drug wears off, people experience a depressed mood and often crave the drug to regain the good feelings.
Regular heroin use changes the functioning of the brain. Using heroin repeatedly can result in:
- tolerance: more of the drug is needed to achieve the same “high”
- dependence: the need to continue use of the drug to avoid withdrawal symptoms
- addiction: a devastating brain disease where, without proper treatment, people have trouble stopping using drugs even when they really want to and even after it causes terrible consequences to their health and other parts of their lives. Because of changes to how the brain functions after repeated drug use, people that are addicted crave the drug just to feel “normal.”
Learn more about how the brain works and what happens when a person uses drugs. And, check out how the brain responds to natural rewards and to drugs.