Siegel (1975), summarized in Turkanan (1987) ’s work, illustrates the powerful influences that classical conditioning can exert on drug action. Derived from this, we can say that if the drug-receptor interaction was the only issue of importance in dependency behaviour, then anyone who ever used a drug would be addicted. As addiction is the exception rather than the mean, this may mean other processes are far more important in determining dependency that drug action alone. Expect recreational drug use to decline once it goes out of fashion and stops being “cool”. This has happened in New York with crack cocaine. It is now no longer “cool” and is much less common. Fashion seems more powerful than the pharmacology of addiction.