Drugs are often taken to
a. alter an individual's mood
b. increase concentration on problems
c. increase depression
d. none of the above

It is to alter an individual's mood Because A drug that is used to prevent disease, fight pathogens, relieve pain and promote health. So Man can think that it will be useful to his decrease Actually whether it is used or not, but human mind thinks that Doctor says that this drug will useful to me. so his belief going to depend on doctor's word. So Drugs are often taken to alter an individual's mood. Tolerance is a state that develops when the body becomes used to the effects of a medicine; requires larger doses of the medicine to produce the same effect.