Dr. Robert Copeland 2001 Drug Abuse refers to the use, usually by self-administration, of any drug in an excessive and persistent use without or deviating from the approved or accepted medical practice. This broad definition of drug abuse also includes the habitual use of drugs like laxatives, headache remedies, antacids and vitamins. The abuse of some drugs can lead to drug dependence - a condition in which the user has a compelling desire to continue taking the drug either to experience its effects or to avoid the discomfort of its absence.
Drug dependence is a general term which is applicable to all types of drug abuse.
Moreover, when the availability of the drug is uncertain, individuals may exhibit a preoccupation with its procurement. Psychologic dependence varies from person to person and with the drug and thus represents a complex interaction of personality factors and specific drug effects. Physical Dependence - An altered or adaptive physiologic state produced in an individual by the repeated administration of a drug. Physical dependence manifest itself as intense physiologic disturbances called the withdrawal or abstinence syndrome . The degree of physical dependence can be measured only by the severity of the withdrawal symptoms.