These are two names for the same disorder.

Manic anything has extreme highs and lows, yet most people are diagnosed that and don’t even have highs and lows, all due to insurance companies. Bi-polar is one or more issues, meaning changes in personalities and changes in emotions and feelings.

There are 2 types of bipolar disorder: Manic depression which varies between manic episodes and depressive episodes and bipolar depression which varies between depressive episodes and normal mood or mild agitation.

Take a look at this link for some insight into your question:

https://psychcentral.com/lib/whats-the-difference-between-depression-and-manic-depression/

Also see:

https://www.webmd.com/bipolar-disorder/bipolar-vs-depression#1