The etiology of hypoactive sexual desire disorder is multifactorial and complex, involving neuroendocrine, psychological, and behavioral factors. It is, however, poorly understood, giving rise to the sense of “bafflement” alluded to by various authors in the literature (Apfelbaum 1988; S. Levine 1988).

It must be remembered that some individuals appear to be constitutionally predisposed to having a sexual drive that lies below a particular point on the sexual drive continuum. We see people, usually women, who report never having experienced sexual drive and yet manifest no psychological, organic, or relationship abnormality on intensive investigation. We also see single women who express concern about their lack of sexual drive and who subsequently experience a sudden appearance, sometimes for the first time in their lives, of sexual drive when they find themselves attracted to and/or in a romantic relationship with a particular partner. Although it could be speculated that, for such women, sexual drive is triggered by pheromones produced by the partner, there is no evidence to support this hypothesis. A more plausible explanation is that in some women (and probably some men, although we have not seen them), sexual drive requires a specific set of conditions in order to be triggered; if these conditions are not met, then their sexual drive is suppressed. Nichols stated that the only thing that triggers sexual desire in women is limerance - that is, a state of infatuation or of being “in love.” In the natural history of most relationships, limerance reduces with time, a circumstance that explains the reduction (and eventual absence) of sexual desire in longer-term relationships. The mechanism by which sexual desire is suppressed in such situations is not understood. It could be that the person ignores the physiological cues upon which the awareness of sexual drive is based.

Psychological Factors

Hypoactive sexual desire disorder is associated with a number of psychological disturbances. Hypoactive sexual desire is a symptom of ongoing depression; Schreiner-Engel and Schiavi found it to be associated with an increased lifetime prevalence of affective disorders in both men and women, as assessed with the Schedule for Affective Disorders and Schizophrenia - Lifetime Version, relative to age-matched control subjects. All of the female patients in this study reported loss of sexual desire during or subsequent to their first episode of affective disorder. Donahey and Carroll reported significant elevations on the depression scale of the Symptom Checklist 90 - Revised (SCL-90-R; Derogatis 1983) in men and women with a primary diagnosis of hypoactive sexual desire disorder, with female patients reporting about twice as much depression as male patients. However, Trudel et al. found only clinically insignificant increased levels of depression assessed by the Beck Depression Inventory. Moderately higher levels of anxiety (measured by the Institute for Personality and Ability Testing [IPAT] Anxiety Scale [Cattell and Scheier 1961]) were also found in patients with hypoactive sexual desire relative to control subjects. Compared with male patients with hypoactive sexual desire and subjects without desire-related problems who served as controls, female patients with hypoactive sexual desire were found to have significant increases on the anxiety, hostility, and paranoid-ideation subscales of the SCL-90-R.

Broadly speaking, identifiable psychological factors contributing to low sexual desire appear to fall into six main areas: sexual trauma, body-image disruption, relationship conflict/habituation, conditioning factors/familial patterns, cultural factors and religious orthodoxy, and life-event factors.

Sexual trauma With growing awareness of the extent to which sexual abuse affects the childhood and/or adolescence of perhaps as many as 1 in 3 women and 1 in 8 men and a recognition of the potential long-term impact of such abuse on partnership and sexual enjoyment, the issue of sexual trauma is increasingly encountered in clinical settings. Many individuals who have experienced abuse, particularly by someone close to or integrated into their family structure, have significant difficulty establishing sexual intimacy in adult life. Hypo- or hypersexuality may ensue. Similar sequelae may follow rape or any form of sexual assault, irrespective of when such an assault occurs in the life span. Although problems with trust are likely to be less profound in individuals who have experienced sexual trauma at the hands of non-family members (as opposed to familial perpetrators), fear and anxiety in a range of social and sexual situations may be serious inhibitors of relationship formation and maintenance. Such experiences are much more likely to lead to lowered levels of desire than to elevated sexual drive.

Body-image disruption Surgery, chronic illness, eating disorders, and the gradual or sudden onset of disabilities all imply potential disruption of body image, with resultant loss of social and sexual confidence and, frequently, libido as well. Expectation of such consequences tends to be associated with obviously sexualized parts of the body: the breasts in women and the genitalia in men and women. This association of anticipated problems with sexual anatomy is restrictive. It brings with it a tendency to downplay aspects of disrupted body image that may have an equally if not a more far-reaching impact. The negative effects of some head and neck cancers are a good example of this. Anxiety or revulsion related to the condition in either the patient or the partner may seriously compromise face-to-face interaction and kissing. The loss of this contact and intimacy means, for many couples, the loss of irreplaceable forerunners of sexual activity.

Relationship conflict/habituation “Clinicians are pretty much in agreement that the major cause of hypoactive sexual desire is marital conflict”. Marital adjustment has been found to be less adequate in patients with low sexual desire than in subjects without this sexual problem. Marital or partnership conflict is a potent etiological and maintenance factor in couples presenting with dysfunctions of desire. Relationship habituation and the resulting sexual and emotional boredom can be just as destructive in its deadening power as overt hostility and frequently reduces the sexual energy levels of one or both partners to a minimum. The importance of novelty to the maintenance of interest in being sexual is recognized, both in the literature and in common mythology.

When relationship assessment reveals a severe relationship conflict, couples therapy is usually indicated before any useful psychosexual therapy is possible. Initiating such therapy often involves referral to another agency, and the prospect of further delay and being required to tell their story all over again can leave the couple feeling disheartened. Careful exploration of this possibility with all couples presenting with disorders of desire is thus important preparation for those who need to go and address fundamental problems elsewhere before perhaps returning to the psychosexual clinic setting to address what is specifically sexual.

Conditioning factors/familial patterns When low levels of drive and desire form an important component of self-concept that has been reinforced and rewarded by prevailing family values relating to “good behavior,” becoming more sexually active may be threatening for both the individual and the wider unit. Not only does there have to be a concerted effort to work against a set of conditioned and established behaviors, but the individual must potentially also risk familial disapproval and distress. Women are particularly susceptible to negative conditioning of this kind, as it is strongly echoed by social mores that assert that “nice girls don’t.” Such patients may have ongoing difficulties with motivation and tend to present because their partner finds the sexual situation unsustainable or because children are suffering from the impact of consequent relationship conflict.

Achieving sexual satisfaction from a particular sexual behavior appears to be an important reinforcer for sexual desire directed at that sexual behavior. Hence, if a person never, or only rarely, achieves satisfaction from, say, making love with a particular partner, there is no reinforcement to make that person continue this behavior, and loss of sexual desire occurs. One way of viewing sexual satisfaction is how near what we get out of a particular sexual behavior comes to what we had expected to get out of it. Many patients who present with loss of sexual desire have unrealistic expectations and are therefore rarely satisfied.

Cultural factors and religious orthodoxy It tends to be the human interpretations of religious and moral codes, with their associated social sanctions, that have the capacity to cause individuals and couples profound distress by impinging on sexual choices and relationships. Gender stereotypes (often clearly prescriptive about sexual interaction) may be well-established components of cultural and religious expectations, and noncompliance can lead to the rejection of individuals by communities, with serious consequences. The intolerance of particular objects of desire regularly leads to the experience of thwarted desire, confusion, and despair. Where two cultures with different value systems meet, conflicting expectations can frame what presents as loss of desire. Expectations of romantic/nonromantic love or of women as sexually active/passive may hold one partner in an uncomfortable cross-tide where experienced dissatisfaction is not compatible with community codes of practice and behavior. Couples in this position are notoriously challenging to work with.

Life-event factors Among the life-event factors that contribute etiologically to hypoactive sexual desire disorder, childbirth and employment issues appear to be two of the more important. We see an increasing number of patients - usually men - of all ages whose loss of sexual desire occurred after they lost their employment or were passed over for a promotion in their career. Presumably in these patients, loss of self-esteem is the operative factor with respect to their loss of sexual desire. Patients sometimes present with loss of sexual desire as a result of being overoccupied in their careers, working long hours at the office and often taking work home out of office hours. Although the loss of sexual desire in some of these people can be explained in terms of stress or fatigue, others just do not seem to have time for sex; it drops off their agenda.

Women often cite the birth of their first or a subsequent child as signaling the beginning of a reduction in sexual motivation, exacerbated by weariness fueled by a multiplicity of demands.

Organic Factors

Organic factors implicated in the etiology of hypoactive sexual desire disorder are poorly understood but include the following.

Endocrine factors In men, loss of sex drive may be the presenting symptom of hypogonadism arising from either testicular or hypothalamo-pituitary dysfunction. Men with loss of sexual drive are also seen who have isolated low serum free testosterone levels, secondary to increased sex hormone-binding globulin levels. More rarely, we see men whose loss of sexual drive is associated with normal to high levels of circulating testosterone but raised levels of serum luteinizing hormone. These men probably have a degree of androgen-receptor resistance. Loss of sexual drive is also associated with hyperprolactinemia, even in the absence of hypogonadism. Presumably in this situation, the increased prolactin secretion is a marker for decreased central dopaminergic activity, which is the cause of the loss of sexual drive.

Loss of sexual drive in women can result from disturbances in the hypothalamic-pituitary-gonadal endocrine axis. In particular, a marked reduction in serum testosterone levels, such as can occur following chemotherapy or radiotherapy, causes sexual problems, including loss of sexual drive. In a recent report, lifelong absence of sexual drive in a woman was found to be associated with low serum 5-dihydrotestosterone levels. As in men, low sexual drive in women may also be associated with hyperprolactinemia. It is our experience that sex-hormone abnormalities are rarely found in women presenting with low sexual drive when there are no other symptoms or conditions suggesting endocrine disturbance.

In both sexes, low sexual drive has been found to be the presenting symptom of thyroid dysfunction (both hypothyroidism and hyperthyroidism), correction of which restores sexual drive in the majority of cases.

Physical illness Illness that can impair the neuroendocrine control mechanisms for sexual drive (e.g., hepatic disease, hemochromatosis, certain brain tumors, pituitary tumors, epilepsy) might be expected to change sexual drive levels. In addition, any debilitating disease or one that causes marked concern can reduce sexual desire. Chronic diseases, mutilating surgery, or radiotherapy may also be associated with loss of sexual desire mediated through changes in self-image and self-esteem.

Drugs There are numerous reports in the literature of drugs being implicated in changes in sexual desire. The majority of such reports are anecdotal, with no real attempt made by the authors to substantiate the claim. Some drugs might be expected to impair sexual drive on pharmacological grounds. These include dopaminergic antagonists, drugs that increase central 5-hydroxytriptamine activity, antiandrogens, gonadotropin agonists (repeated dosing), some chemotherapeutic agents, and drugs that increase sex hormone-binding globulin production. Other drugs might impair sexual desire through nonspecific effects such as sedation and changes in cognitive functioning. The issue of drug-induced sexual dysfunction is complex and outside the scope of this chapter.