Interpersonal and contextual factors

In a recent national probability sample of American women 20–65 years of age, their emotional relationship with the partner during sexual activity and general emotional well-being were the 2 strongest predictors of absence of distress about sex. Women who defined themselves (using standard psychological instruments) to be in good mental health were much less likely than women with lower self-rated mental health to report distress about their sexual relationship (odds ratio 0.41, 95% confidence interval 0.29– 0.59). The healthier women were therefore 59% less likely to report distress about their sexual relationship. Feeling emotionally close to their partner during sexual activity decreased the odds of "slight distress" by 33% relative to "no distress," and "marked distress" by 43%; in other words, the stronger the emotional intimacy with the partner, the less distress. Other contextual factors reported to reduce arousability included concerns about safety (risks of unwanted pregnancy and STDs, for example, or emotional or physical safety), appropriateness or privacy, or simply that the situation is insufficiently erotic, too hurried, or too late in the day.

Personal psychological factors

Frequently a woman's arousal is precluded by the nonsexual distractions of daily life, but also sometimes by sexual distractions (e.g., worry about not becoming sufficiently aroused, reaching orgasm, a male partner's delayed or premature ejaculation or a female partner's lack of orgasm). Empirical studies have shown a high correlation of desire complaints with measures of low self-image, mood instability and tendency toward worry and anxiety (without meeting the clinical definition of a mood disorder). Differences between a group of 46 consecutive women with a diagnosis of desire disorder without clinical depression and a control group of 100 healthy women were significant for 6 out of 8 scales in the Narcissism Inventory (a standardized self-administered instrument). The scales indicated that the women with desire disorder had self-esteem that was weak or even fragile, emotional instability, anxiety and neuroticism. Sexual arousal and orgasm, especially in a partner's presence, necessitates a certain degree of vulnerability, which is impossible for some women who cannot tolerate feelings of loss of control generally, and loss of control specifically of their body's reactions.

Further inhibiting psychological factors include memories of past negative sexual experiences, including those that have been coercive or abusive, and expectations of negative outcomes to the sexual experience (e.g., from dyspareunia or partner sexual dysfunction).

Biological factors

The biological and pathophysiological underpinnings of normal and abnormal female sexual response are only recently receiving attention. Most of the basic science and animal experiments in this area are beyond the scope of this review. Some promising attempts are noted, however, in part because they relate attempts to ameliorate sexual dysfunction by means of off-label use of available drugs and to avoid the negative sexual side-effects of medications such as antidepressants.

Depression is strongly associated with reduced sexual function. Of 79 women with major depression surveyed before treatment with medication, 50% reported decreased sex drive; 50%, more difficulty obtaining vaginal lubrication; and 50%, far less sexual arousal when engaging in sex. Only 50% had been sexually active during the previous month. In addition, sexual dysfunction can constitute an adverse event of antidepressant use, especially among patients who had low levels of sexual enjoyment before the onset of their depression. When patients are specifically asked about sexual side-effects, they are acknowledged by as many as 70%.

Sexual dysfunction is also a common side-effect of treatment with antidepressants. Among women being treated, it has been found to be more common in those who are older, married, without postsecondary education, without full-time work, or taking concomitant medication (any type); those who have a comorbid illness that might affect sexual functioning, or a history of antidepressant - associated sexual dysfunction; those who deem sexual function unimportant; and those whose previous sexual engagements had afforded little pleasure.

Currently under scrutiny is the role of dopamine and other neurotransmitters in influencing sex hormone receptors and how the neurotransmitters are, in turn, influenced by sex hormones. Estrogenized female animals change their sexual behaviour when administered progesterone; studies have shown that the same changes can result from dopamine or the presence of a male animal. Among 75 non-depressed women with a DSM-IV diagnosis of hypoactive sexual desire disorder who received bupropion (a dopaminergic drug; average dose 389 mg/ d) or placebo, improvements in pleasure, arousal and orgasm were statistically significant for those administered the active drug. Interestingly, these changes were unaccompanied by increased desire.

Testosterone itself is being investigated as to its role in sexual function and dysfunction. About half of daily testosterone production in women is from the ovary. Some women with sudden loss of all ovarian production of androgens lose their sexual arousability. Supplementation to high physiological (as opposed to pharmacologically evident) levels of testosterone recently has led to increased arousability and more intense orgasmic experiences, but not to increased sexual thinking, fantasizing or spontaneous desire. Of 75 surgically menopausal women aged 31–56 participating in a randomized clinical trial of testosterone versus placebo, those given testosterone (300 μg transdermally) in addition to estrogen reported increased frequency of sexual activity, sexual pleasure and intensity of orgasm. So, reminiscent of the animal model, supplementation with a dopaminergic drug or testosterone can increase some women's sexual arousability; but so too, as in the animal model, can environmental change (a new partner).