Depression Support Group
Depression is a real and debilitating condition that is often misunderstood by family and friends. Its meaning can range from a prolonged period of sadness to an actual mental illness with specific symptoms. Find and share experiences with others who are going through the same struggles.

I think you're right that she says she "wants to be locked up" because she doesn't want to deal with responsibilities. (I seriously doubt she really wants to be locked up in a mental institution.) It sounds to me like she feels better from the meds and therapy and now she is sort of using the depression as a way to keep you from pushing her on schoolwork and grades.
I don't know why the therapist told you not to remind her about her schoolwork/grades. It seems to me that as a parent, your job is to help her learn and grow into a productive happy adult. Personally, I disagree with the therapist on that.
Can you talk to her therapist again about this issue? And find out more about why you're not supposed to bring up grades with your daughter? I don't think you should just let her stay home whenever she wants, or let her fail classes.
Your daughter says she doesn't feel any better than before, but you noticed a positive change in her. It sounds like she's bringing up her depression as a way to get out of doing her schoolwork.
'Depressed' people still have responsibilities and having 'depression' is not to be used as an excuse to not do what we are supposed to do.
You cannot hide depression nor can you hide happiness ... and if she were clinically depressed she would be depressed just about ALL the time. Only with school? Sorry, it doesn't work that way.
You're being 'had' in my opinion. She has some kind of serious problem with school, but depression is not it. You need to find out what it is about school that she detests .. and work on that with her ... so should the therapist.
I'm curious about a couple of things that might change my response though. How severe did her doctor say her depression was last fall? Is any of this behavior new or worse?
Let me share my story so you can see if there are really any similarities. When I was 16, I went to therapy a handful of times, but we had no money to continue. My mom sent me because I was depressed. What she didn't know was that I had panic attacks several times a day, was suicidal (1 attempt) and self-injured.
I also missed a lot of school (1/3 of the school year). Sometimes it was because I just couldn't function. Other times, it was because I couldn't be around people. I thought they either could see my weakness or I had to fake it to hide my weakness, and that's just draining even when you're not depressed.
I also thought I should be in a white, padded room. I thought this because I was so overwhelmed, and couldn't deal with life anymore. It was the only thing I could think of that we keep me alive.
Most of the time, I did look like I was okay, just like now. I always knew enough to fake happy so people wouldn't harass me about why I'm not happy. Typically though, my happy was a bit more exaggerated than my normal happy - party too much, talk/laugh too much, smile non-stop, completely hyperactive even though I'm not ADHD/ADD, etc.
Naturally, I was failing a lot of classes too. I just couldn't focus because I was either drowning in depression, or trying my damndest to pretend I wasn't. This was not my normal. I had always been an A-B student, usually A.
I'm not saying this is definitely what's happening with your daughter, but it is a possibility. My suggestion is to schedule and maintain a regular therapy visit regardless of what she says (if she doesn't talk about it, it's not really happening).
With hindsight being 20/20, I really should have been admitted to an inpatient program. Frankly, it's a miracle I made it out of my teens. Please feel free to reach out to me if you need any other input.
Since your daughter is just 16 you still have the opportunity to make decisions for her and you should probably let her know that you have decided she needs to go back to her therapist and maybe the three of you can work things out, before she falls further behind in school and before she is 18. I wish you luck and strength. If all else fails you should make an appointment with the therapist, I wish I had.
Nobody wants to believe their child is suffering from severe depression. Sadly teenage suicide rates show the terrible reality. I'm not trying to scare you or say that your daughter is in any way suicidal. I'm just saying that you need to treat this seriously.
My son suffered with depression as a teen. The advice that I'm passing on to you was given to me by professionals. So please get your daughter in to see a doctor.
It's so hard as a parent to think of our children being seriously depressed. If you would like to message me I would try to help in any way that I can. Hugs Kelley