Some psychoactive drugs work as , meaning that they artificially stimulate receptors in a neurotransmitter system. Others work as , meaning that they block activity at particular receptors.

1.Agonists

2.Antagonists

Explanation:

An agonist drug attaches to both the receptor which induces the reaction inside the cell. An antagonist can attach to the very same receptor, but will not generate a response, rather it stops the receptor from a natural agonist.

Antagonism can be successful and offset by elevated agonist levels. Unmanageable antagonists are firmly bound to a transmitter and therefore are not removed by an external agonist.