I always have the tendency toward depression. But I have gone through whole weeks and months of not feeling depressed. Never a whole year. I don't take medication but I did take St. John's Wort for several years and I have been in therapy continuously for four years. The last thing that really helped my depression was by attending 12-step meetings. I am taking a break from them right now and I can tell. Depressed on and off for the last few days.

No.

Yes. But... In my case I wouldn't call it remission because I do not take medication. This isn't to say that one can't experience a remission without taking medication. I just think for that it is much harder. (IMO)

I think so. I think after years of the right medication and a good therapist one can experience a remission. This has happened to my partner and to the author Andrew Solomon (for example).