I was recently forwarded the following article from the Denver Post discussing how crack-cocaine is less appealing for drug dealers in Rio De Janeiro due to its associated societal costs.  While an interesting read, it also reminds us of the reinforcing and ultimately destructive nature of crack cocaine.

Drug reinforcement is an unconscious process involving the midbrain and neural structures such as the nucleus accumbens, ventral tegmental area, and locus coeruleus.  We know this from ongoing research and neuroimaging through the NIH and NIDA.  The most reinforcing of all drugs of abuse is believed to be cocaine as determined through animal studies.  A classic example of this is that of a laboratory rat.  When given levers to dispense either food or cocaine, the rat will continually press the cocaine-dispensing lever.  This is continued at the expense of health, leading ultimately to death by starvation.  More recent studies show that cocaine dependency is highly linked to deep memories of drug use.  When shown images of people using crack, an addict often experiences pleasure as if he or she were using the drug.

Keep in mind that addiction is fundamentally about compulsive behavior.  Our primitive brains, similar to those of the laboratory rat, connect to such substances as cocaine leading to continued use despite ongoing life consequences.