Thus the psychopathologized individual for Freud was an immature individual, and the goal of psychoanalysis was to bring these fixations to conscious awareness so that the libido energy would be freed up and available for conscious use in some sort of constructive sublimation. Analytical psychology
According to Swiss psychiatrist Carl Gustav Jung, the libido is identified as the totality of psychic energy, not limited to sexual desire. As Jung states in "The Concept of Libido," "[libido] denotes a desire or impulse which is unchecked by any kind of authority, moral or otherwise. Libido is appetite in its natural state. From the genetic point of view it is bodily needs like hunger, thirst, sleep, and sex, and emotional states or affects, which constitute the essence of libido." The 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) These symbols may manifest as "fantasy-images" in the process of psychoanalysis which embody the contents of the libido, otherwise lacking in any definite form. Desire, conceived generally as a psychic longing, movement, displacement and structuring, manifests itself in definable forms which are apprehended through analysis. Defined more narrowly, libido also refers to an individuals urge to engage in sexual activity, and its antonym is the force of destruction termed mortido or destrudo.
Factors that affect libido
Endogenous compounds
Libido is governed primarily by activity in the mesolimbic dopamine pathway (ventral tegmental area and nucleus accumbens). Consequently, dopamine and related trace amines (primarily phenethylamine) that modulate dopamine neurotransmission play a critical role in regulating libido.Other neurotransmitters, neuropeptides, and sex hormones that affect sex drive by modulating activity in or acting upon this pathway include:

Testosterone (directly correlated) – and other androgens
Estrogen (directly correlated) – and related female sex hormones
Progesterone (inversely correlated)
Oxytocin (directly correlated)
Serotonin (inversely correlated)
Norepinephrine (directly correlated)
Acetylcholine

Sex hormone levels and the menstrual cycle
A womans desire for sex is correlated to her menstrual cycle, with many women experiencing a heightened sexual desire in the several days immediately before ovulation, which is her peak fertility period, which normally occurs two days before and until two days after the ovulation. This cycle has been associated with changes in a womans testosterone levels during the menstrual cycle. According to Gabrielle Lichterman, testosterone levels have a direct impact on a womans interest in sex. According to her, testosterone levels rise gradually from about the 24th day of a womans menstrual cycle until ovulation on about the 14th day of the next cycle, and during this period the womans desire for sex increases consistently. The 13th day is generally the day with the highest testosterone levels. In the week following ovulation, the testosterone level is the lowest and as a result women will experience less interest in sex.Also, during the week following ovulation, progesterone levels increase, resulting in a woman experiencing difficulty achieving orgasm.