Libido

Libido (/lɪˈbiːdoʊ/; colloquial: sex drive) is a person's overall sexual drive or desire for sexual activity. Libido is influenced by biological, psychological, and social factors. Biologically, the sex hormones and associated neurotransmitters that act upon the nucleus accumbens (primarily testosterone and dopamine, respectively) regulate libido in humans.[1] Social factors, such as work and family, and internal psychological factors, such as personality and stress, can affect libido. Libido can also be affected by medical conditions, medications, lifestyle and relationship issues, and age (e.g., puberty). A person who has extremely frequent or a suddenly increased sex drive may be experiencing hypersexuality, while the opposite condition is hyposexuality.

For other uses, see Libido (disambiguation).

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. Conversely, a person can engage in sexual activity without an actual desire for it. Multiple factors affect human sex drive, including stress, illness, pregnancy, and others. A 2001 review found that, on average, men have a higher desire for sex than women.[2]

Sexual desires are often an important factor in the formation and maintenance of intimate relationships in humans. A lack or loss of sexual desire can adversely affect relationships. Changes in the sexual desires of any partner in a sexual relationship, if sustained and unresolved, may cause problems in the relationship. The infidelity of a partner may be an indication that a partner's changing sexual desires can no longer be satisfied within the current relationship. Problems can arise from disparity of sexual desires between partners, or poor communication between partners of sexual needs and preferences.[3]

Psychological perspectives

Psychoanalysis

Sigmund Freud

Sigmund Freud, who is considered the originator of the modern use of the term,[4] defined libido as "the energy, regarded as a quantitative magnitude... of those instincts which have to do with all that may be comprised under the word 'love'."[5] It is the instinct energy or force, contained in what Freud called the id, the strictly unconscious structure of the psyche. He also explained that it is analogous to hunger, the will to power, and so on[6] insisting that it is a fundamental instinct that is innate in all humans.[7]

Freud developed the idea of a series of developmental phases in which the libido fixates on different erogenous zones—first in the oral stage (exemplified by an infant's pleasure in nursing), then in the anal stage (exemplified by a toddler's pleasure in controlling his or her bowels), then in the phallic stage, through a latency stage in which the libido is dormant, to its reemergence at puberty in the genital stage.[8] (Karl Abraham would later add subdivisions in both oral and anal stages.)[9]

Freud pointed out that these libidinal drives can conflict with the conventions of civilised behavior, represented in the psyche by the superego. 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. Excessive use of ego defenses results in neurosis. 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.[10]

Freud viewed libido as passing through a series of developmental stages within the individual. Failure to adequately adapt to the demands of these different stages could result in libidinal energy becoming 'dammed up' or fixated in these stages, producing certain pathological character traits in adulthood. 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.[11][12] As Jung states in "The Concept of Libido,"[13] "[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.[14] 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 individual's urge to engage in sexual activity, and its antonym is the force of destruction termed mortido or destrudo.[15]

Factors that affect libido

Endogenous compounds

See also: Sexual motivation and hormones

Libido is governed primarily by activity in the mesolimbic dopamine pathway (ventral tegmental area and nucleus accumbens).[1] Consequently, dopamine and related trace amines (primarily phenethylamine)[16] that modulate dopamine neurotransmission play a critical role in regulating libido.[1]

Other neurotransmitters, neuropeptides, and sex hormones that affect sex drive by modulating activity in or acting upon this pathway include:

• Testosterone[1] (directly correlated) – and other androgens[17][18][19][20]
• Estrogen[1] (directly correlated) – and related female sex hormones[21][22][23][24][25]
• Progesterone[24] (inversely correlated)
• Oxytocin[26] (directly correlated)
• Serotonin[27][28][29] (inversely correlated)
• Norepinephrine[27]
• Acetylcholine[30]

Sex hormone levels and the menstrual cycle

A woman's desire for sex is correlated to her menstrual cycle, with many women experiencing a heightened sexual desire in the several days immediately before ovulation,[31] which is her peak fertility period, which normally occurs two days before until two days after the ovulation.[32] This cycle has been associated with changes in a woman's testosterone levels during the menstrual cycle. According to Gabrielle Lichterman, testosterone levels have a direct impact on a woman's interest in sex. According to her, testosterone levels rise gradually from about the 24th day of a woman's menstrual cycle until ovulation on about the 14th day of the next cycle, and during this period the woman's 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.[17]

Also, during the week following ovulation, progesterone levels increase, resulting in a woman experiencing difficulty achieving orgasm. Although the last days of the menstrual cycle are marked by a constant testosterone level, women's libido may get a boost as a result of the thickening of the uterine lining which stimulates nerve endings and makes a woman feel aroused.[33] Also, during these days, estrogen levels decline, resulting in a decrease of natural lubrication.

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. However, the levels of testosterone increase at menopause and this may be why some women may experience a contrary effect of an increased libido.[34]

Psychological and social factors

Certain psychological or social factors can reduce the desire for sex. These factors can include lack of privacy or intimacy, stress or fatigue, distraction or depression. Environmental stress, such as prolonged exposure to elevated sound levels or bright light, can also affect libido. Other causes include experience of sexual abuse, assault, trauma, or neglect, body image issues, and anxiety about engaging in sexual activity.[35]

Individuals with PTSD may find themselves with reduced sexual desire. Struggling to find pleasure, as well as having trust issues, many with PTSD experience feelings of vulnerability, rage and anger, and emotional shutdowns, which have been shown to inhibit sexual desire in those with PTSD.[36] Reduced sex drive may also be present in trauma victims due to issues arising in sexual function. For women, it has been found that treatment can improve sexual function, thus helping restore sexual desire.[37] Depression and libido decline often coincide, with reduced sex drive being one of the symptoms of depression.[38] Those suffering from depression often report the decline in libido to be far reaching and more noticeable than other symptoms.[38] In addition, those with depression often are reluctant to report their reduced sex drive, often normalizing it with cultural/social values, or by the failure of the physician to inquire about it.

Physical factors

Physical factors that can affect libido include endocrine issues such as hypothyroidism, the effect of certain prescription medications (for example flutamide), and the attractiveness and biological fitness of one's partner, among various other lifestyle factors.[39]

In males, the frequency of ejaculations affects the levels of serum testosterone, a hormone which promotes libido. A study of 28 males aged 21–45 found that all but one of them had a peak (145.7% of baseline [117.8%–197.3%]) in serum testosterone on the 7th day of abstinence from ejaculation.[40]

Anemia is a cause of lack of libido in women due to the loss of iron during the period.[41]

Smoking, alcohol abuse, and the use of certain drugs can also lead to a decreased libido.[42] Moreover, specialists suggest that several lifestyle changes such as exercising, quitting smoking, lowering consumption of alcohol or using prescription drugs may help increase one's sexual desire.[43][44]

Medications

Some people purposefully attempt to increase their libido through the usage of anaphrodisiacs.[45] Aphrodisiacs, such as dopaminergic psychostimulants, are a class of drugs which can increase libido. On the other hand, a reduced libido is also often iatrogenic and can be caused by many medications, such as hormonal contraception, SSRIs and other antidepressants, antipsychotics, opioids and beta blockers.

Many SSRIs can cause a long term decrease in libido and other sexual functions, even after users of those drugs have shown improvement in their depression and have stopped usage.[38][46] Multiple studies have shown that with the exception of bupropion (Wellbutrin), trazodone (Desyrel) and nefazodone (Serzone), antidepressants generally will lead to lowered libido.[38] SSRIs that typically lead to decreased libido are fluoxetine (Prozac), paroxetine (Paxil), fluvoxamine (Luvox), citalopram (Celexa) and sertraline (Zoloft).[38] There are several ways to try and reap the benefits of the antidepressants while maintaining high enough sex drive levels. Some antidepressant users have tried decreasing their dosage in the hopes of maintaining an adequate sex drive. Results of this are often positive, with both drug effectiveness not reduced and libido preserved. Other users try enrolling in psychotherapy to solve depression-related issues of libido. However, the effectiveness of this therapy is mixed, with lots reporting that it had no or little effect on sexual drive.[38]

Testosterone is one of the hormones controlling libido in human beings. Emerging research[47] is showing that hormonal contraception methods like oral contraceptive pills (which rely on estrogen and progesterone together) are causing low libido in females by elevating levels of sex hormone binding globulin (SHBG). SHBG binds to sex hormones, including testosterone, rendering them unavailable. Research is showing that even after ending a hormonal contraceptive method, SHBG levels remain elevated and no reliable data exists to predict when this phenomenon will diminish.[48]

Oral contraceptives lower androgen levels in users, and lowered androgen levels generally lead to a decrease in sexual desire. However, usage of oral contraceptives has shown to typically not have a connection with lowered libido in women.[49] Multiple studies have shown that usage of oral contraceptives is associated with either a small increase or decrease in libido, with most users reporting a stable sex drive.[50]

Effects of age

Males reach the peak of their sex drive in their teenage years, while females reach it in their thirties.[51][52] The surge in testosterone hits the male at puberty resulting in a sudden and extreme sex drive which reaches its peak at age 15–16, then drops slowly over his lifetime. In contrast, a female's libido increases slowly during adolescence and peaks in her mid-thirties.[53] Actual testosterone and estrogen levels that affect a person's sex drive vary considerably.

Some boys and girls will start expressing romantic or sexual interest by age 10–12. The romantic feelings are not necessarily sexual, but are more associated with attraction and desire for another. For boys and girls in their preteen years (ages 11–12), at least 25% report "thinking a lot about sex".[54] By the early teenage years (ages 13–14), however, boys are much more likely to have sexual fantasies than girls. In addition, boys are much more likely to report an interest in sexual intercourse at this age than girls.[54] Masturbation among youth is common, with prevalence among the population generally increasing until the late 20s and early 30s. Boys generally start masturbating earlier, with less than 10% boys masturbating around age 10, around half participating by age 11–12, and over a substantial majority by age 13–14.[54] This is in sharp contrast to girls where virtually none are engaging in masturbation before age 13, and only around 20% by age 13–14.[54]

People in their 60s and early 70s generally retain a healthy sex drive, but this may start to decline in the early to mid-70s.[55] Older adults generally develop a reduced libido due to declining health and environmental or social factors.[55] In contrast to common belief, postmenopausal women often report an increase in sexual desire and an increased willingness to satisfy their partner.[56] Women often report family responsibilities, health, relationship problems, and well-being as inhibitors to their sexual desires. Aging adults often have more positive attitudes towards sex in older age due to being more relaxed about it, freedom from other responsibilities, and increased self-confidence. Those exhibiting negative attitudes generally cite health as one of the main reasons. Stereotypes about aging adults and sexuality often regard seniors as asexual beings, doing them no favors when they try to talk about sexual interest with caregivers and medical professionals.[56] Non-western cultures often follow a narrative of older women having a much lower libido, thus not encouraging any sort of sexual behavior for women. Residence in retirement homes has affects on residents libidos. In these homes, sex occurs, but it is not encouraged by the staff or other residents. Lack of privacy and resident gender imbalance are the main factors lowering desire.[56] Generally, for older adults, being excited about sex, good health, sexual self-esteem and having a sexually talented partner.[57]

Sexual desire disorders

See also: Hyposexuality and Hypersexuality

Simplified representation

There is no widely accepted measure of what is a healthy level for sex desire. Some people want to have sex every day, or more than once a day; others once a year or not at all. However, a person who lacks a desire for sexual activity for some period of time may be experiencing a hypoactive sexual desire disorder or may be asexual.

A sexual desire disorder is more common in women than in men,[58] and women tend to exhibit less frequent and less intense sexual desires than men.[59] Erectile dysfunction may happen to the penis because of lack of sexual desire, but these two should not be confused.[60] For example, large recreational doses of amphetamine or methamphetamine can simultaneously cause erectile dysfunction and significantly increase libido.[61] However, men can also experience a decrease in their libido as they age.

The American Medical Association has estimated that several million US women suffer from a female sexual arousal disorder, though arousal is not at all synonymous with desire, so this finding is of limited relevance to the discussion of libido.[41] Some specialists claim that women may experience low libido due to some hormonal abnormalities such as lack of luteinising hormone or androgenic hormones, although these theories are still controversial. Also, women commonly lack sexual desire in the period immediately after giving birth. Moreover, any condition affecting the genital area can make women reject the idea of having intercourse. It has been estimated that half of women experience different health problems in the area of the vagina and vulva, such as thinning, tightening, dryness or atrophy. Frustration may appear as a result of these issues and because many of them lead to painful sexual intercourse, many women prefer not having sex at all. Surgery or major health conditions such as arthritis, cancer, diabetes, high blood pressure, coronary artery disease or infertility may have the same effect in women.[3] Surgery that affects the hormonal levels in women include oophorectomies.

See also

• Desire
• Lust
• Sexual arousal
• Sexual attraction
• Sexual desire
• Sexual motivation and hormones

References

1. Fisher HE, Aron A, Brown LL (December 2006). "Romantic love: a mammalian brain system for mate choice". Philos. Trans. R. Soc. Lond. B Biol. Sci. 361 (1476): 2173–86. doi:10.1098/rstb.2006.1938. PMC 1764845. PMID 17118931. The sex drive evolved to motivate individuals to seek a range of mating partners; attraction evolved to motivate individuals to prefer and pursue specific partners; and attachment evolved to motivate individuals to remain together long enough to complete species-specific parenting duties. These three behavioural repertoires appear to be based on brain systems that are largely distinct yet interrelated, and they interact in specific ways to orchestrate reproduction, using both hormones and monoamines. ... Animal studies indicate that elevated activity of dopaminergic pathways can stimulate a cascade of reactions, including the release of testosterone and oestrogen (Wenkstern et al. 1993; Kawashima &Takagi 1994; Ferrari & Giuliana 1995; Hull et al. 1995, 1997, 2002; Szezypka et al. 1998; Wersinger & Rissman 2000). Likewise, increasing levels of testosterone and oestrogen promote dopamine release ...This positive relationship between elevated activity of central dopamine, elevated sex steroids and elevated sexual arousal and sexual performance (Herbert 1996; Fiorino et al. 1997; Liu et al. 1998; Pfaff 2005) also occurs in humans (Walker et al. 1993; Clayton et al. 2000; Heaton 2000). ... This parental attachment system has been associated with the activity of the neuropeptides, oxytocin (OT) in the nucleus accumbens and arginine vasopressin (AVP) in the ventral pallidum ... The activities of central oxytocin and vasopressin have been associated with both partner preference and attachment behaviours, while dopaminergic pathways have been associated more specifically with partner preference.
2. Roy F. Baumeister, Kathleen R. Catanese, and Kathleen D. Vohs. "Is There a Gender Difference in Strength of Sex Drive? Theoretical Views, Conceptual Distinctions, and a Review of Relevant Evidence" (PDF). Department of Psychology Case Western Reserve University. Lawrence Erlbaum Associates, Inc. All the evidence we have reviewed points toward the conclusion that men desire sex more than women. Although some of the findings were more methodologically rigorous than others, the unanimous convergence across all measures and findings increases confidence. We did not find a single study, on any of nearly a dozen different measures, that found women had a stronger sex drive than men. We think that the combined quantity, quality, diversity, and convergence of the evidence render the conclusion indisputableCS1 maint: multiple names: authors list (link)
3. "Low sex drive in women". Retrieved July 28, 2010.
4. Crowe, Felicity; Hill, Emily; Hollingum, Ben (2010). Sex and Society. New York: Marshall Cavendish. p. 462. ISBN 9780761479055.
5. S. Freud, Group Psychology and the Analysis of the Ego, 1959
6. Malabou, Catherine (2012). The New Wounded: From Neurosis to Brain Damage. New York: Fordham University Press. p. 103. ISBN 9780823239672.
7. Klages, Mary (2017). Literary Theory: The Complete Guide. London: Bloomsbury Publishing. p. 245. ISBN 9781472592767.
8. Sigmund Freud, New Introductory Lectures on Psychoanalysis (PFL 2) p. 131
9. Otto Fenichel, The Psychoanalytic Theory of Neurosis (1946)p. 101
10. Reber, Arthur S.; Reber, Emily S. (2001). Dictionary of Psychology. New York: Penguin Reference. ISBN 0-14-051451-1.
11. P. Gay, Freud (1989) p. 397
12. Sharp, Daryl. "Libido". frithluton.com.
13. “The Concept of Libido,” Collected Works Vol. 5, par. 194.
14. “The Technique of Differentiation,” Collected Works Vol. 7, par. 345.
15. Eric Berne, A Layman's Guide to Psychiatry and Psychoanalysis (1976) p. 69 and 101
16. Miller GM (January 2011). "The emerging role of trace amine-associated receptor 1 in the functional regulation of monoamine transporters and dopaminergic activity". J. Neurochem. 116 (2): 164–176. doi:10.1111/j.1471-4159.2010.07109.x. PMC 3005101. PMID 21073468.
17. Lichterman, Gabrielle (November 2004). 28 Days: What Your Cycle Reveals about Your Love Life, Moods, and Potential. ISBN 978-1-59337-345-0.
18. Harding SM, Velotta JP (May 2011). "Comparing the relative amount of testosterone required to restore sexual arousal, motivation, and performance in male rats". Horm Behav. 59 (5): 666–73. doi:10.1016/j.yhbeh.2010.09.009. PMID 20920505.
19. Davis SR, Moreau M, Kroll R, Bouchard C, Panay N, Gass M, Braunstein GD, Hirschberg AL, Rodenberg C, Pack S, Koch H, Moufarege A, Studd J (November 2008). "Testosterone for low libido in postmenopausal women not taking estrogen". N. Engl. J. Med. 359 (19): 2005–17. doi:10.1056/NEJMoa0707302. PMID 18987368.
20. Renneboog B (2012). "[Andropause and testosterone deficiency: how to treat in 2012?]". Revue Médicale de Bruxelles. 33 (4): 443–9. PMID 23091954.
21. DeLamater, J.D.; Sill, M. (2005). "Sexual Desire in Later Life". The Journal of Sex Research. 42 (2): 138–149. doi:10.1080/00224490509552267. PMID 16123844.
22. Heiman JR, Rupp H, Janssen E, Newhouse SK, Brauer M, Laan E (May 2011). "Sexual desire, sexual arousal and hormonal differences in premenopausal US and Dutch women with and without low sexual desire". Horm. Behav. 59 (5): 772–779. doi:10.1016/j.yhbeh.2011.03.013. PMID 21514299.
23. Warnock JK, Swanson SG, Borel RW, Zipfel LM, Brennan JJ (2005). "Combined esterified estrogens and methyltestosterone versus esterified estrogens alone in the treatment of loss of sexual interest in surgically menopausal women". Menopause. 12 (4): 359–60. doi:10.1097/01.GME.0000153933.50860.FD. PMID 16037752.
24. Ziegler, T. E. (2007). Female sexual motivation during non-fertile periods: a primate phenomenon. Hormones and Behavior, 51(1), 1–2
25. Simerly, Richard B. (2002-03-27). "Wired for reproduction: organization and development of sexually dimorphic circuits in the mammalian forebrain" (PDF). Annu. Rev. Neurosci. 25: 507–536. doi:10.1146/annurev.neuro.25.112701.142745. PMID 12052919. Archived from the original (PDF) on 2008-10-01. Retrieved 2007-03-07.
26. McGregor IS, Callaghan PD, Hunt GE (May 2008). "From ultrasocial to antisocial: a role for oxytocin in the acute reinforcing effects and long-term adverse consequences of drug use?". Br. J. Pharmacol. 154 (2): 358–368. doi:10.1038/bjp.2008.132. PMC 2442436. PMID 18475254. Recent evidence suggests that popular party drugs such as MDMA and gamma-hydroxybutyrate (GHB) may preferentially activate brain oxytocin systems to produce their characteristic prosocial and prosexual effects. Oxytocin interacts with the mesolimbic dopamine system to facilitate sexual and social behaviour, and this oxytocin-dopamine interaction may also influence the acquisition and expression of drug-seeking behaviour.
27. Clayton AH (July 2010). "The pathophysiology of hypoactive sexual desire disorder in women". Int J Gynaecol Obstet. 110 (1): 7–11. doi:10.1016/j.ijgo.2010.02.014. PMID 20434725.
28. Hu XH, Bull SA, Hunkeler EM, et al. (July 2004). "Incidence and duration of side effects and those rated as bothersome with selective serotonin reuptake inhibitor treatment for depression: patient report versus physician estimate". The Journal of Clinical Psychiatry. 65 (7): 959–65. doi:10.4088/JCP.v65n0712. PMID 15291685.
29. Landén M, Högberg P, Thase ME (January 2005). "Incidence of sexual side effects in refractory depression during treatment with citalopram or paroxetine". The Journal of Clinical Psychiatry. 66 (1): 100–6. doi:10.4088/JCP.v66n0114. PMID 15669895.
30. Int J Impot Res. 2000 Oct;12 Suppl 4:S26-33.
31. Susan B. Bullivant; Sarah A. Sellergren; Kathleen Stern; et al. (February 2004). "Women's sexual experience during the menstrual cycle: identification of the sexual phase by noninvasive measurement of luteinizing hormone". Journal of Sex Research. 41 (1): 82–93 (in online article, see pp.14–15, 18–22). doi:10.1080/00224490409552216. PMID 15216427. Archived from the original on 2007-09-23.
32. "Archived copy". Archived from the original on 2008-12-21. Retrieved 2008-09-22.CS1 maint: archived copy as title (link)
33. "Women Can Now Predict When They Will Have The Best Sex". Retrieved July 28, 2010.
34. Shearer, Jasmin L; Salmons, Nabeel; Murphy, Damian J; Gama, Rousseau (January 2017). "Postmenopausal hyperandrogenism: the under-recognized value of inhibins". Annals of Clinical Biochemistry. 54 (1): 174–177. doi:10.1177/0004563216656873. ISSN 0004-5632. PMID 27278937.
35. Yalom, I.D., Love's Executioner and Other Tales of Psychotherapy. New York: Basic Books, 1989. ISBN 0-06-097334-X.
36. Yehuda, Rachel; Lehrner, Amy; Rosenbaum, Talli Y. (2015). "PTSD and Sexual Dysfunction in Men and Women". The Journal of Sexual Medicine. 12 (5): 1107–1119. doi:10.1111/jsm.12856. ISSN 1743-6109. PMID 25847589.
37. Wells, Stephanie Y.; Glassman, Lisa H.; Talkovsky, Alexander M.; Chatfield, Miranda A.; Sohn, Min Ji; Morland, Leslie A.; Mackintosh, Margaret-Anne (2019-01-01). "Examining Changes in Sexual Functioning after Cognitive Processing Therapy in a Sample of Women Trauma Survivors". Women's Health Issues. 29 (1): 72–79. doi:10.1016/j.whi.2018.10.003. ISSN 1049-3867. PMID 30455090.
38. Robert L. Phillips, Jr; Slaughter, James R. (2000-08-15). "Depression and Sexual Desire". American Family Physician. 62 (4): 782–786. ISSN 0002-838X. PMID 10969857.
39. Psychology Today – The orgasm Wars Archived 2007-10-02 at the Wayback Machine
40. Jiang, M.; Xin, J.; Zou, Q.; Shen, J. W. (2003). "A research on the relationship between ejaculation and serum testosterone level in men". Journal of Zhejiang University Science. 4 (2): 236–240. doi:10.1631/jzus.2003.0236. PMID 12659241.
41. "Lack of sex drive in men (lack of libido)". Retrieved July 28, 2010.
42. Mayo Clinic. "Low sex drive in women". Mayo Foundation for Medical Education and Research (MFMER). Retrieved 14 January 2020.
43. Finley, Nicola (2017). "Lifestyle Choices Can Augment Female Sexual Well-Being". American Journal of Lifestyle Medicine. 12 (1): 38–41. doi:10.1177/1559827617740823. PMC 6125014. PMID 30283244.
44. Mayo Clinic. "Low sex drive in women: Diagnosis and Treatment". Mayo Foundation for Medical Education and Research (MFMER). Retrieved 14 January 2020.
45. Rebal Jr, Ronald F., Robert A. Faguet, and Sherwyn M. Woods. "Unusual sexual syndromes." Extraordinary Disorders of Human Behavior. Springer US, 1982. 121-154.
46. Bala, Areeg; Nguyen, Hoang Minh Tue; Hellstrom, Wayne J. G. (2018-01-01). "Post-SSRI Sexual Dysfunction: A Literature Review". Sexual Medicine Reviews. 6 (1): 29–34. doi:10.1016/j.sxmr.2017.07.002. ISSN 2050-0521. PMID 28778697.
47. Warnock, J. K.; Clayton, A.; Croft, H.; Segraves, R.; Biggs, F. C. (2006). "Comparison of Androgens in Women with Hypoactive Sexual Desire Disorder: Those on Combined Oral Contraceptives (COCs) vs. Those not on COCs". The Journal of Sexual Medicine. 3 (5): 878–882. doi:10.1111/j.1743-6109.2006.00294.x. PMID 16942531..
48. Panzer, C.; Wise, S.; Fantini, G.; Kang, D.; Munarriz, R.; Guay, A.; Goldstein, I. (2006). "Impact of Oral Contraceptives on Sex Hormone-Binding Globulin and Androgen Levels: A Retrospective Study in Women with Sexual Dysfunction". The Journal of Sexual Medicine. 3 (1): 104–113. doi:10.1111/j.1743-6109.2005.00198.x. PMID 16409223..
49. Burrows, Lara J.; Basha, Maureen; Goldstein, Andrew T. (2012-09-01). "The Effects of Hormonal Contraceptives on Female Sexuality: A Review". The Journal of Sexual Medicine. 9 (9): 2213–2223. doi:10.1111/j.1743-6109.2012.02848.x. ISSN 1743-6095. PMID 22788250.
50. Davis, Anne R.; Castaño, Paula M. (2004). "Oral contraceptives and libido in women". Annual Review of Sex Research. 15: 297–320. ISSN 1053-2528. PMID 16913282.
51. Reconceiving the second sex Marcia Claire Inhorn – 2009
52. Principles and practice of adult health nursing Patricia Gauntlett Beare
53. Leonard Shlain (July 27, 2004), Sex, Time, and Power, Penguin (Non-Classics), p. 140, ISBN 9780142004678, OL 7360364M
54. Fortenberry, J. Dennis (July 2013). "Puberty and Adolescent Sexuality". Hormones and Behavior. 64 (2): 280–287. doi:10.1016/j.yhbeh.2013.03.007. ISSN 0018-506X. PMC 3761219. PMID 23998672.
55. Lehmiller, Justin J (2018). The Psychology of Human Sexuality. Wiley Blackwell. pp. 621–626. ISBN 9781119164692.
56. Sinković, Matija; Towler, Lauren (2018-12-25). "Sexual Aging: A Systematic Review of Qualitative Research on the Sexuality and Sexual Health of Older Adults". Qualitative Health Research. 29 (9): 1239–1254. doi:10.1177/1049732318819834. ISSN 1049-7323. PMID 30584788.
57. Kontula, Osmo; Haavio-Mannila, Elina (2009-02-03). "The Impact of Aging on Human Sexual Activity and Sexual Desire". The Journal of Sex Research. 46 (1): 46–56. doi:10.1080/00224490802624414. ISSN 0022-4499. PMID 19090411.
58. Segraves, K. B.; Segraves, R. T. (2008). "Hypoactive Sexual Desire Disorder: Prevalence and Comorbidity in 906 Subjects". Journal of Sex & Marital Therapy. 17 (1): 55–58. doi:10.1080/00926239108405469. ISSN 0092-623X. PMID 2072405.
59. Baumeister, Roy F.; Catanese, Kathleen R.; Vohs, Kathleen D. (2001). "Is There a Gender Difference in Strength of Sex Drive? Theoretical Views, Conceptual Distinctions, and a Review of Relevant Evidence". Personality and Social Psychology Review. 5 (3): 242–273. doi:10.1207/S15327957PSPR0503_5. ISSN 1088-8683.
60. "Lack of sex drive in men (lack of libido)". Retrieved July 28, 2010.
61. Gunne LM (2013). "Effects of Amphetamines in Humans". Drug Addiction II: Amphetamine, Psychotogen, and Marihuana Dependence. Berlin, Germany; Heidelberg, Germany: Springer. pp. 247–260. ISBN 9783642667091. Retrieved 4 December 2015.

Further reading

• Ellenberger, Henri (1970). The Discovery of the Unconscious: The History and Evolution of Dynamic Psychiatry. New York: Basic Books. Hardcover ISBN 0-465-01672-3, softcover ISBN 0-465-01672-3.
• Froböse, Gabriele, and Froböse, Rolf. Lust and Love: Is It More than Chemistry? Michael Gross (trans. and ed.). Royal Society of Chemistry, ISBN 0-85404-867-7 (2006)
• Giles, James, The Nature of Sexual Desire, Lanham, Maryland: University Press of America, 2008.