Mood stabilizers

Can someone please explain to me the purpose of mood stabilizers? I know the name sounds obvious but how do they differ from anti depressants and how do they help? Thank you.

[c-mac]

For some people, being depressed can lead to being manic or hypomanic, and then back again, in a cycle. Mania is when you are suddenly brave and inappropriate, maybe you think you're unstoppable or super charismatic. Or it can just make you really angry, I hear. The problem with some people is that when you give them anti-depressants to deal with being down, it can actually launch them into being too "up", or manic. So mood stabilizers help stop the cycle. Some of them also have properties that treat either the manic or the depressive phases. Lamictal, which I take, is also good at preventing depression. I think lithium, another one, helps with mania.