Yes and no, probably. This is entirely from my experience and my knowledge/research. I am no professional so do take my words with a grain of salt.
Depression, much like most people do, will always hit everyone at one point in their lifes. As people 'recover', they tend to be able to let go off their past and experience to better their future. One example, experiencing their loved ones die. Yes they'll go through grief but as it prolong, depression would hit them and their way of living would deteriorate. Most would be able to crawl their way out of that hole and live better lives. But some would need assistance like therapy, medication, support groups, etc. At the end of the day, they'll soon join those people who are carrying out their normal lives. That's the general side of depression.
Meanwhile clincal depression, or major depressive disorder, or chronic depression, it has a few names, don't really go away unfortunately. In most sources, medication would be most effective for those who are in the major stage. Some would probably need medication and therapy. It is highly unlikely you'll be 'cured' once you start improving because it'll probably come back. Usually the cause would be a trigger like remembering traumatic event or bad memory, having a stressful life or illness. However, it's not like you're back to square one. Much like other illnesses, as long as you start treating it early, you could recover. I would describe it like how my doctor described it to me,
"It's like a broken bone. A broken bone is more vulnerable than an undamaged bone." So your treatment is like a cast to assist it's healing.
However, there are those few are unfortunate enough, to be genetically depressed due to chemical imbalances. The process of those who are like this is similar to treating clinical depression but it takes extra effort. Treatment for these people is like a lifetime. Some of those who developed into major depressive disorder can be treated, but it'll probably revert back to minor depression. It isn't as severe from the name but it could be as destructive because its like a slow burning disease. An again, with triggers or being untreated for a long time, could develop into major depressive disorder again. Well, atleast thats what I experienced. For the years that I have been battling depression, I'm starting to believe I can never be cured. Ever day feels very empty and cold. The things that excites me or motivates me are limited. Some days, nothing keeps me motivated. It takes extra effort to achieve happiness and anytime I'm start being alone I just feel nothing. Every night I just hope to understand this emptiness and at most times when I'm with friends or family, I feel so alone even though it is evident that they love me. I stopped taking medication not because I feel like it wasn't working, I just know that theres no hope in taking it anymore. Ill just keep on relapsing. Plus I wouldn't want to feel awful everytime I took those piils. It takes time take effect, but it destroyed my soul. So I lied to my doctor that I'm getting better and I stopped going for medical check ups. And I did lost hope.
But, what keeps me going is those acts of love that i got from friends and family. It makes me feel like I'm part of this world and I am glad they are setting an example for me to show what it means to love. So as I give back to them, it somewhat soothe my soul/heart. Being part of their lives and watching them grow as I do, makes me feel happy.
Again, do take my words with a grain of salt. Most of what I said are from my own knowledge and experience and I'm not a professional. I'm just a lucky guy who won the genetic lottery. But even luckier because I have amazing people around me who keeps me going. If they aren't there, I probably wouldn't want to be in this world. This world is sad enough, and my eyes just made it even sadder. But right now, all I could see are my loved ones and I appreciate that. In conclusion, I'm just coping. I can never recover. I hope I covered some useful information for you. Good Night.