The generic name is the chemical name while their brand name is a name given by the drug company that manufactures and sells them.
Generic drugs are much cheaper than brand-name drugs.
The newer antidepressants are available only as brand name drugs, which is one reason they are more expensive. The first antidepressants were prescribed back in the 1950s. Many of these medications had serious, even life-threatening side effects which limited their usefulness. Each type has advantages and disadvantages. All are effective and there's absolutely no sure way to determine ahead of time which antidepressant will help a certain person.