Excerpts from The Alcoholism and Addiction Cure

Alcohol Dependency and Psychological Dependence

Alcohol dependency is characterized by craving, loss of control, tolerance, physical and/or psychological dependence, and the production of withdrawal symptoms. It should be noted that developing "tolerance" doesn't mean that we can no longer get drunk, but that it takes more alcohol to get us drunk than it did when we first began drinking. One of the more insidious - meaning slowly and subtly destructive - aspects of alcohol is that it erodes our "stop mechanisms," or our ability to stop drinking. The process occurs so slowly and subtly that we're unaware that our stop mechanisms are being eroded. This becomes obvious only when we try to stop but can't. Even though I usually mention drugs and alcohol separately, they are the same in that alcohol is actually the drug ethanol (CH₃CH₂OH). Ethanol is toxic and nearly all of it is processed in your liver, which leads to cirrhosis.

CIRRHOSIS
According to the Mayo Clinic,
"Cirrhosis is a condition that causes irreversible scarring of the liver. As scar tissue replaces normal tissue, blood flow through your liver is affected, making it increasingly difficult for your liver to carry out functions that are essential for life and health. Among other major tasks, the liver detoxifies harmful substances, purifies your blood and manufactures vital nutrients."
Alcohol actually scars your liver. Since the liver cannot feel that type of pain, we can literally drink ourselves to death. It is never a pretty death, because we are slowly poisoned by the toxins our livers can no longer filter out. If your liver could feel that type of pain, you would never consume your second drink.

PSYCHOLOGICAL DEPENDENCE
In addition to physical dependence, we can develop psychological dependence. "Psychic need" is the perceived need to use a substance to cope with unpleasant feelings such as despondency, heartache, anxiety, stress, or depression. Relief from something unpleasant is a kind of reward called "negative reinforcement." That cycle is worsened by both the physical and psychological discomforts felt during abstinence. When we stop using the addictive drugs or alcohol that we've been using to cope with unpleasant feelings, those feelings return, as does the strong desire to return to the substances that enabled us to cope with them. That's what characterizes psychological dependence.