The National Institute on Drug Abuse estimates that nearly $500 billion are spent each year on abuse or addiction to alcohol and nicotine as well as illegal substances. Alcohol is a central nervous system depressant that impairs and ultimately changes the brain. Alcohol crosses into the bloodstream, spreads quickly throughout the body, and begins affecting the drinker because it passes the blood-brain barrier. Ultimately, the altered neurochemistry of the drinker maintains the addiction.
Classification
Addiction, according to NIDA, is classified as a brain disease. It is a physically chronic disease like heart or renal disease because addiction leads to actual changes in the function and structure of the brain. Alcohol addiction is a chronic disease characterized by compulsive drug seeking and use, regardless of the dangerous consequences.
Time and Quantity
Alcohol addiction is a gradual disease that develops over time to the point where the alcoholic's brain changes in response to the excessive alcohol intake. The Mayo Clinic states that more than 15 drinks per week for men and more than 12 drinks per week for women may lead to addiction, but time frames for developing this addiction will vary depending on the individual.
Pleasure System
The way that alcohol makes people feel is the payoff or reward that motivates the behavior; specifically, the pleasure system in the brain is activated by alcohol use. Thus, the pleasure sensations produced by alcohol sets up a craving to re-experience the rewarding sensations. Alcohol activates an immediate increase in dopamine, a neurotransmitter, or chemical messenger, that frequently is called the pleasure chemical, according to the Mayo Clinic. Eventually, the addicted brain becomes pleasure-driven, which overrides behavioral control and consequences.
Neurotransmitter Disturbance
Nerve cells in the brain, called neurons, communicate with each other via small junctions called synapses. An activated neuron releases chemicals into the synapse called neurotransmitters. GABA, or gamma-aminobutyric acid, is a chemical that inhibits neuron excitement as well as impulsive behaviors by producing a sedative effect that promotes relaxation, euphoria, and calmness in opposition to glutamate. Glutamate is an excitatory neurotransmitter that balances out GABA effects. Alcohol disrupts this balancing process and triggers high levels of GABA in addition to the dopamine, according to the Mayo Clinic.
Psychological Dependence
Alcohol can be psychologically addictive, because anxiety and stress are affected by GABA. The inhibitory effects of GABA, which results in relaxation and calmness, drive psychological dependence, for the person comes to believe that alcohol is necessary to help with daily distress.
Tolerance and Physical Dependence
Over time, the neurons adjust and the new disturbed levels of neurotransmitters with their high dopamine and GABA levels become the norm. Consequently, greater amounts of alcohol are needed to get the same dopamine rush as before; this effect is known as tolerance. With the changed neurochemistry, alcohol is now needed to maintain functioning---the body is physically dependent on alcohol. The absence of alcohol at this point causes a neurochemical imbalance with painful consequences known as withdrawal symptoms.
