The relationship between neurotransmitters and addiction is founded in the addictive substance's ability to interrupt neurotransmitter brain activity. Neurotransmitters are message carriers sent between a neuron and a receptor. Pain, pleasure, boredom, and other messages travel by neurotransmitter. Drugs, alcohol, and other addictive substances not only prevent appropriate neurotransmitter activity, but also create brain activity that changes behavior.
Dopamine is a primary neurotransmitter impacted by addiction. This neurotransmitter affects movement control, emotions, pleasure, and pain. Different drugs can stimulate or inhibit the brain's dopamine receptors. This interferes with the neurotransmitter's ability to work effectively.
Cocaine is one example of a drug that impacts dopamine action in the brain. Using cocaine increases dopamine levels and creates a temporary euphoria. Each drug used either blocks or stimulates the neurotransmitters, which impacts the user's thoughts and behaviors. Some drugs, including amphetamines, disrupt the normal flow of the brain's neurotransmitters. Other drugs bypass the neurotransmitter system completely and go directly to receptors.
When dopamine neurotransmitters are consistently overstimulated through drug use, the brain stops creating dopamine on its own. This is called desensitization, often referred to as drug tolerance. Desensitization takes weeks to months to reverse itself after the drug use is eliminated.
Different drugs have different connections between neurotransmitters and addiction. For example, amphetamines increase dopamine release, and cocaine binds to the neurotransmitter,reducing dopamine release, yet both drugs produce feelings of happiness and energy. The level and speed of changes in brain chemicals with drug use also have an impact on neurotransmitters as well as addiction.
Due to the effect of certain drugs on neurotransmitters and addiction, some drugs are considered more addictive than others. Crack cocaine and opiates including heroin, morphine, and prescription painkillers are considered extremely addictive. Marijuana is considered much less addictive. Nicotine is considered the most addictive of the psychoactive drugs.
Chronic drug use, as seen in addiction, has an impact on the brain's function. Neurotransmitters and addiction are studied in an effort to understand their relationship and find a cure. Research has discovered chronic drug use changes the frontal cortex of the brain. This is the area responsible for understanding consequences of actions. Not learning from mistakes, not worrying about risk, and not caring about consequences are all byproducts of the relationship between neurotransmitters and addiction.