Is the field of psychoneuroimmunology.
I think in a learning environment it can not provide a positive purpose. It can cause you to lose focus as well as others around you.
In McCulloch v. Maryland (1819) the Supreme Court ruled that Congress had implied powers under the Necessary and Proper Clause of Article I, Section 8 of the Constitution to create the Second Bank of the United States and that the state of Maryland lacked the power to tax the Bank.