I don't know. I do know that great sorrow is a misunderstood value in our culture. It is considered negative and it is not sought by most spiritual seekers. We call great joy an ultimate healthy state and one which universalizes us, connecting us to god in all things. But, we fearfully choose to denigrate and deny great sorrow by calling it personal pathology.
Great sorrow is transcendent.
You are connected with everything, you are full. You are illuminated. It feels like a flood. It is not depression, but profound sadness. If you respond with fear the experience may indeed change to depression, but of itself, great sorrow is part of love.