Is it cosidered the same as a mortgage?

More or less. I think the principal difference is that the borrower didn't purchase the home with it; it's borrowed on an already-owned home. The detailed terms of the mortgage might be a bit different, but it's still a secured loan.

See Home equity loan (http://en.wikipedia.org/wiki/Home_equity_loan).

A mortgage is any type of loan where the property is used as collateral for the loan. When a person takes out a mortgage as part of the purchase of property it is called a purchase money mortgage. When a person takes out a mortgage on property that they already own it is usually called a home equity loan.

A mortgage is any type of loan where the property is used as collateral for the loan. ...

Well, a deed of trust is a real property collateral arrangement too. But they serve the same purpose.