Think it depends sometimes on the cause of the depression. I had never had real depression in my life until I was about 42 & then it was a situation that hit my life that caused me to feel that way & then I didn't realize it but the condition that I had been living it that had been masked by my career was really the foundation of the depression & when my career was no longer there to mask it, the loss of the career & the condition I had been living in for so long all came crashing down on me.

It took 13 years before I was able to leave that situation after that point....but during those years I didn't realize really what was causing the depression at that point & neither did any of the T's or psychiatrists but there wasn't a med that helped so I knew it had to do with situation & not chemical imbalance. I didn't have good therapy during those years either so accomplished nothing.

Went through a trauma at the end of that time so I piled PTSD on top of the anxiety & the depression & anorexia on top of that so I was a mess by the time I was finally able to LEAVE....but once I left all that behind, I started to get better & I started to be able to see what had been going on in the life that was so much like being in the middle of a forest.

There is no specific time frame that depression lasts.....depends on the person, the situation (if it's situational) & something the ability for meds to help.