Short answers, pulled from the story.
Substance dependence is a biopsychological state where functionality becomes dependent on the re-consumption of a psychoactive substance. When an individual develops this adaptive state, the discontinuation of the drug results in withdrawal symptoms that range from physical somatic distress to emotional and motivational turmoil.
Heroin and morphine scored a perfect 3.0 across all categories of physical dependence, psychological dependence, and pleasure. Tobacco showed a mean score of 2.21 with a psychological dependence score of 2.6.
The Diagnostic and Statistical Manual of Mental Disorders released in 2013 eliminated the distinction between substance abuse and substance dependence, replacing them with the single diagnosis of substance use disorders. This change was implemented because the tolerance and withdrawal that previously defined dependence are actually very normal responses to prescribed medications that affect the central nervous system.
In the United States and many developing countries, the goal of commissioners of treatment for drug dependence is generally total abstinence from all drugs. Other countries, particularly in Europe, argue the aims of treatment for drug dependence are more complex, with treatment aims including reduction in use to the point that drug use no longer interferes with normal activities such as work and family commitments.
Morphine was isolated in the early 19th century and came to be prescribed commonly by doctors, both as a painkiller and as an intended cure for opium addiction. Addiction to opium became widespread among soldiers fighting in the Civil War, who very often required painkillers and thus were very often prescribed morphine.