How addictive is heroin / morphine?
The only real answer to this question is “it depends.” That is, it depends on what you mean by “addiction” and the individual and the environment in which they find themselves. For example, there are some people who are said to be “addicted” to gambling. The problem is that gambling has no physical substance. If people can become “addicted” to something with no physical substance, then we should ask ourselves what “addiction” really means, and how “addictive” a physical substance is when things with no substance can cause “addiction.” In an attempt to define clearly what is meant by addiction, and which drugs are the most addictive, Dr. Jack E. Henningfield of the National Institute on Drug Abuse and Dr. Neal L. Benowitz of the University of California at San Francisco ranked six psychoactive substances on five criteria. • Withdrawal — The severity of withdrawal symptoms produced by stopping the use of the drug. • Reinforcement — The drug’s tendency to induce users to take it again a
