" Against all expectations, the symptoms of Van Gogh’s mental illness are conspicuous by their almost complete absence from his letters. Much as he chose not to paint before he had fully recovered from one of his attacks, so he refrained from writing at times of crisis. Throughout his life, admittedly, his letters bear witness to a man possessed, frequently agitated, enraged, dejected, obsessed, but never deranged, or emotionally or intellectually unstable. "

― Vincent van Gogh , The Letters of Vincent van Gogh