Abuse of central nervous system (CNS) stimulants is common. Addiction to some CNS stimulants can quickly lead to medical, psychiatric, and psychosocial deterioration. Drug tolerance, dependence, and sensitization as well as a withdrawal syndrome can occur.
The judicial branch decides what amendments are unconstitutional as well as acts of the president. However, if the judicial branch were to declare an act of the president unconstitutional, it would mean that Congress agreed to this act.
Each branch has some powers to override the actions of other branches: Both houses of Congress must vote to enact a law, thereby checking power within the legislature; President can veto legislation; Supreme Court can rule federal and state laws unconstitutional; Congress can reject legislation the president wants; override vetoes by a 2/3rds vote; impeach and remove president; declare war