Depression is more of a mental thing than a physical thing.

It's not easy to cure depressions, and medications are used to contain it, rather than to effective treat it.

To overcome depression, I guess it's up to the individual to fight their way out of it.

It's hard to overcome depressions, best thing to do is refer to a psychologist, and check into therapy.

It does not mean one will recover fully, nor one would change.

Some people just grow out of depressions, some fallen even deeper and etc. It's different for every different individual.

Medicine can't cure depression.

It only suppresses it.

Get that fact correctly.

Best thing for you to do as a Friend is to be supportive. That's all.