The compounds ordinarily classified as central stimulants are drugs that increase behavioral activity, thought processes, and alertness or elevate the mood of an individual. These drugs differ widely ...The compounds ordinarily classified as central stimulants are drugs that increase behavioral activity, thought processes, and alertness or elevate the mood of an individual. These drugs differ widely in their molecular structures and in their mechanism of action. Thus, describing a drug as a stimulant does not adequately describe its medicinal chemistry. The convulsions induced by a stimulant such as strychnine, for example, are very different from agitation induced by amphetamine.