Answer to Question 1
Substance intoxication refers to the physiological reaction to an ingested substance. The degree of intoxication is related to the drug used, how much is ingested, and the person's individual biological reaction. Substance abuse according to DSM-IV-TR is defined in terms of how significantly it interferes with the user's life. If it disrupts your education, job, relationships, health, or well-being, or causes legal problems, it can be judged as abuse. Substance dependence is described as an addiction. It can involve physiological reactions to the chemicals being ingested, and may include tolerance and withdrawal, but does not have to. In general, the term addiction is used to describe people who are under the control of a drug or drugs.
Answer to Question 2
a