I encourage people to help them. Start off with simple feelings like disappointment before something like depression. We've addressed how depression can affect one's sex life. Now here's a question about anxiety. If a bad guy holds a gun up to a guy's head and tells him he'll shoot him if he doesn't get an erection, then that guy is dead.
Anxiety prevents women from having orgasms and prevents men from getting aroused.
It could be anxiety about what you are thinking, stress, your life, etc. At the neurological level, the process of sexual arousal requires a portion of the nervous system that must be relaxed for it to respond. If it is anxious, then few to none of the sexual arousal things will happen. In sex therapy, we get people comfortable with their sexuality. We teach them to communicate and be comfortable.