Research has revealed that the drugs most commonly abused by humans (including opiates, alcohol, nicotine, amphetamines, and cocaine) create a neurochemical reaction that significantly boosts the amount of dopamine released by neurons in the brain's reward center. Many activities can stimulate dopamine production, such as sex, exercise, nicotine from cigarettes, and recreational drugs like heroin or cocaine. While sex encourages the natural release of dopamine, drugs can trigger a huge amount of dopamine. This abundance can lead to that euphoric feeling of pleasure. However, when you're so high and immersed in a dopamine wave, you have to fall even lower when that dopamine wave subsides, thus the overwhelming feeling that many drug users experience when their euphoria wears off.
Many of the side effects of drugs on brain chemistry can be reversed when drugs are processed outside the body after a period of time. However, some medications may have a longer lasting effect. Drugs such as methamphetamine can damage up to half of the dopamine-producing cells (and perhaps even more of the serotonin-containing nerve cells) in the brain with chronic exposure, warns the Drug Enforcement Administration (DEA). This damage may only be partially reversible, since chronic methamphetamine users may suffer from memory problems, learning problems, psychosis, aggression, emotional dysfunction and even develop Parkinson's disease as a result of functional and structural changes in the brain that may persist for years after they stop using it, reports NIDA. A pleasant experience, a burst of dopamine indicates that something important is happening that needs to be remembered.
It's one of the reasons you might want to use drugs when you return to where you once used them long after you've stopped. To send a message, a neuron releases a neurotransmitter into the space (or synapse) between it and the next cell. In many ways, the psychological deterioration associated with these potentially hazardous activities mimics what happens when people use drugs recreationally. Each substance has slightly different effects on the brain, but all addictive drugs such as alcohol, opioids and cocaine produce a pleasant surge of the neurotransmitter dopamine in a region of the brain called the basal ganglia; neurotransmitters are chemicals that transmit messages between nerve cells. Regular drug use actually causes the brain to produce, absorb or transmit less dopamine, resulting in a chemical imbalance in the brain.
In a report, PBS referred to methamphetamine as “the mother of all” referring to drugs that produce powerful surges of dopamine. The chemicals that make us feel good in the brain such as dopamine decrease making people feel a little exhausted after feeling on top of the world. Usually when something makes a person feel happy a signal is sent to the VTA (ventral tegmental area) that travels to the nucleus accumbens and then to the prefrontal cortex explains the National Institute on Drug Abuse (NIDA). When medical experts talk about how addiction changes brain chemistry they are referring to the chemical changes involving dopamine and the brain's need to replenish the skyrocketing levels reached by drugs. In a recent NPR interview psychiatrist Anna Lembke explained that each of us has a dopamine release baseline.
Dopamine agonists are prescription drugs that can be used alone or in combination with other medications to treat a variety of conditions that result from dopamine loss. This is mainly because older drugs bind to any dopamine receptor available in the body and are not selective. Dopamine reuptake inhibitors are drugs that prevent dopamine from re-entering and being reabsorbed by the nerve cell that released it. Drugs interact with natural chemicals in the brain and virtually all substances that alter the mind have some impact on the brain's reward processing center and pathway.