A depressant is a type of substance that slows down the activity of your brain and nervous system. Think of your nervous system like a busy highway of messages traveling between your brain and body. A depressant is like adding speed bumps that make everything move more slowly.

Doctors sometimes prescribe depressants as medicines to help people who have trouble sleeping or who feel extremely anxious. These medications work by calming down an overactive nervous system. Some types of anesthesia, which doctors use during surgery to make patients unconscious, act as powerful depressants.

However, depressants can also affect mood and make people feel sluggish or tired.