My depression is the most faithful mistress I have known—no wonder, then, that I return the love.

The line personifies depression as a “mistress,” framing melancholy not as a passing mood but as an intimate, enduring companion—“faithful” in the sense that it reliably returns and never abandons the speaker. The bitter irony is that this constancy invites a kind of reciprocal attachment: one can come to “love” what is familiar, even when it harms. Read in a Kierkegaardian key, it also gestures toward the seductive pull of despair—how a self can cling to its suffering as a form of identity or perverse comfort. The quote captures the paradox of emotional dependence: pain can become the most stable relationship one has.