Libido refers to sexual urge or desire whether this is conscious or instinctive. Normal libido needs an adequate supply of the hormones, testosterone and dopamine that together inhibit another horrmone (prolactin) that lowers libido. A fall in libido may be caused by a fall in hormone levels which can be affected by a physical disorder or by psychological factors. A drain in the psychological energy may be caused by depression, anxiety and feelings of inadequacy all of which could have roots in traumatic events such as rape or incest, guilt feelings, poor self-esteem, chronic fatigue, stress from work, certain religious beliefs, or relationship problems. Individually or together, these events can prevent emotional enjoyment and a decline in the sexual urge. Other interfering factors such as ailments, medications, and pain associated with sexual intercourse may result in sexual disinterest.