Craving is defined as an intense desire for some particular thing. Craving is probably the main driving force behind all addictions. Craving can drive the alcoholic or addict to do things they normally wouldn't do, like committing crimes or choosing alcohol or drugs over a wife or children. One way of thinking of addiction is continuing to drink, use drugs, or participate in an addiction despite negative consequences. The cravings spur obsession (a persistent disturbing preoccupation with idea or feeling) and compulsion (an irresistible impulse to perform an irrational act) to do it again. It is now known that all addictions eventually involve pathways in the brain that release the naturally occurring neurotransmitter dopamine. When the human being experiences any kind of pleasure or satiation, dopamine is usually involved. This neurotransmitter then is thought to be one of the key factors in the phenomenon of craving. Craving can be induced just by thinking about alcohol, drugs, or involvement in the addiction. And there are a multitude of "triggers" that can rapidly induce craving, such as certain sights, sounds, smells, or tastes. Or to put it another way, craving may partly be a conditioned response to powerful cues such as certain people, places, and things that are associated with drinking, drug use, or the addiction. This is why it is so very difficult for the addict to remain abstinent. Learning about triggers and being prepared to deal with them is very helpful in avoiding relapse. This is a major reason for advising those in early-stage recovery to avoid friends and locations that have previously been associated with alcohol or their particular addiction. Sometimes, even after years of abstinence, and alcoholic or addict can experience profound cravings and be at risk for relapse if placed in surroundings that are considered triggers.