Antidepressants work by affecting neurotransmitter systems in the brain. Neurotransmitters and receptors are the way nerve cells in the brain communicate. A neurotransmitter represents a message sent from one nerve cell to another, and the receptor on the adjacent cell is like the mailbox. Antidepressants increase available levels of some neurotransmitters (messages), which, in turn, improve mood and anxiety. This happens over a period of several weeks.
People commonly refer to antidepressants as “correcting a chemical imbalance,” but this is incorrect. It is more accurate to say the medications create a new equilibrium that results in beneficial brain changes.
We don’t know the exact cause of depression, though it may be the result of a natural response that goes awry at times. But we do know that changing the levels of certain neurotransmitters has a proven, clinically significant impact, and that antidepressants can have therapeutic benefits for patients.