Ans. is 'c' i.e., Psychological dependence Drug dependence Drug dependence, as the name suggests, is a state where a person becomes dependent on a drug despite knowing the harmful effect of the drug. This state arises from repeated, periodic or continuous administration of a drug, that results in harm to the individual. The subject feels a desire, need or compulsion to continue using the drug and feels ill if abruptly deprived of it (withdraw! syndrome) Drug dependency is characterized by the triad of : i. Psychological dependence First to appear There is emotional distress if the drug is withdrawn ii. Physical dependence Follows psychological dependence There is physical illness if the drug is withdrawn (withdraw! symptoms) iii. Tolerance Tolerance may be Self tolerance - To the drug on which the subject is dependent Cross tolerance - To the other similar (usually) or dissimilar (sometimes) drugs. The frequency of use of drug is usually daily and duration is inevitably greater than 2-3 weeks.