How alcohol cravings get stronger after drinking during with
It is commonly thought that people drink because it makes them feel good. But in people who have developed dependence, the 'feel-good' sensation that the drug produces is actually a reversal of feeling terrible. When this reversal of feeling terrible is experienced repeatedly, then environmental cues that become associated with this experience produce a much more powerful craving than the initial 'feel-good' craving.

Rats that had learned to associate a scent with alcohol during withdrawal were much more persistent in the presence of that scent; during a 30-minute time period, they pressed a lever attempting to obtain alcohol twice as many times as animals that had only been conditioned during early alcohol drinking while not yet dependent. This persistence remained even when they received a small electric shock upon pressing the lever, or when the task of lever pressing was made increasingly more difficult. What we're seeing is that in rats, they'll work much harder to overcome obstacles and are willing to endure adverse consequences if they've been conditioned with cues during withdrawal.

The researchers found that the new conditioning actually weakened older cues that had been learned before the animal became alcohol dependent. If an animal originally associated alcohol with an anise scent, but was later made dependent and conditioned to associate alcohol with an orange scent while drinking during withdrawal, the anise scent was no longer as strong a cue for setting off alcohol-seeking behaviors compared to the second scent that was associated with alcohol drinking during withdrawal. The researchers then studied the amygdala, the part of the brain associated with drug and alcohol addiction in humans and rats, to see how it changed during each conditioning experiment. Different areas, they discovered, were activated depending on whether rats were learning a scent during initial alcohol exposure while not dependent, or during withdrawal after having been made dependent.