Although some specialists disagree with this theory, menopause is still considered by the majority a factor that can cause decreased sex desire in women.
The levels of estrogen decrease at menopause and this usually causes a lower interest in sex and vaginal dryness which makes intercourse painful.
According to Swiss psychiatrist Carl Gustav Jung, the libido is identified as psychic energy.
Duality (opposition) creates the energy (or libido) of the psyche, which Jung asserts expresses itself only through symbols: "It is the energy that manifests itself in the life process and is perceived subjectively as striving and desire." (Ellenberger, 697) Defined more narrowly, libido also refers to an individual's urge to engage in sexual activity, and its antonym is the force of destruction termed mortido or destrudo.
Social factors, such as work and family, and internal psychological factors, like personality and stress, can affect libido.
A person may have a desire for sex, but not have the opportunity to act on that desire, or may on personal, moral or religious reasons refrain from acting on the urge.
Psychologically, a person's urge can be repressed or sublimated.
It is this need to conform to society and control the libido that leads to tension and disturbance in the individual, prompting the use of ego defenses to dissipate the psychic energy of these unmet and mostly unconscious needs into other forms. A primary goal of psychoanalysis is to bring the drives of the id into consciousness, allowing them to be met directly and thus reducing the patient's reliance on ego defenses.
Freud viewed libido as passing through a series of developmental stages within the individual.