Well I think I was a fairly unhappy isfp for the bulk of my teenage years, but I think I approached close to actual depression for a few years in my mid 20's, and it took a long while to break through all of those years of getting stuck in my head and becoming healthy and well balanced again. In my teenage years I was withdrawn to the point of not really socially interacting at all- or at least, there wasn't any actual deepness or intimacy, and I had maybe one or two friends. In my 20's it was more an existential crisis and I think also I was working through everything that had accumulated in my teenage years. I do agree with the above poster that the silver lining ends up being more inner awareness and growth, also it's probably resulted in my having developed Ni way more than I otherwise would have, being pretty much 100% in my head- but very unbalanced and unhappy when in that state, very anxious, stuck. I still externally functioned, did some things socially, maintained a job, all of that, but then would be emotionally overwhelmed when home. So yeah.