The Neurobiology of Drug Addiction

Historically cocaine abuse involved snorting the powdered form (the hydrochloride salt). When cocaine is processed to form the freebase, it can be smoked. Heating the hydrochloride salt form of cocaine will destroy it; the freebase can be volatilized at high temperature without any destruction of the compound. Smoking gets the drug to the brain more quickly than does snorting. Show the audience why this happens. Snorting requires that the cocaine travels from the blood vessels in the nose to the heart (purple arrow), where it gets pumped to the lungs (purple arrow) to be oxygenated. The oxygenated blood (red arrows) carrying the cocaine then travels back to the heart where it is pumped out to the organs of the body, including the brain. However, smoking bypasses much of this, the cocaine goes from the lungs directly to the heart and up to the brain. The faster a drug with addictive liability reaches the brain, the more likely it will be abused. Thus, the time between taking the drug and the positive reinforcing or rewarding effects that are produced can determine the likelihood of abuse.