What is the link between depression and sex?

See below... Most people who are depressed lose interest in sex; such loss has nothing to do with one's partner and everything to do with a psyche that is so depressed that nothing interests it anymore... Including sex...
Biochemistry. Mood and sexuality are all about self regulation and the nervous system and clearly share some important biochemistry. When mood is out of balance sexaul interest often follows in the same direction , optimally both are "evenly" balanced.