The causes of female sexual dysfunction are poorly defined. Several factors may impede the sexual response cycle, which requires physical and psychological stimulation:
- Emotional problems; distraction
- Negative body perception
Recently, controversy has produced two opposing medical perspectives on the causes (and treatment) for female sexual dysfunction. One concept, known as the vascular theory, is that diminished blood flow to the pelvic region, due to a medical condition, aging, stress, or hypoactive sexual desire, causes reduced sensitivity (particularly of the clitoris) and dryness, and impairs arousal. Decreased blood flow is associated with medical conditions such as diabetes and atherosclerosis. This concept has fueled clinical research and has led to the introduction of topical creams that, when applied to the clitoris, cause vascular dilation, increased blood flow, and vascular congestion associated with the excitement stage. Sensitivity is increased and may lead to arousal.
A second concept, the hormone theory, focuses on decreased levels of sex hormones, such as estrogen and testosterone, caused by aging. For some women, hormone replacement therapy leads to greater sexual desire. Estrogen, a primarily female hormone, is associated with sexual desire. Testosterone, a primarily male sex hormone, plays a role in women's sexual development and function, including sensitivity of the breasts and clitoris. Some women experience diminished sexual desire, absence of sexual fantasies, and impaired sensitivity following menopause or hysterectomy as a result of reduced estrogen.
Other medical causes include the following:
- Bicycle riding (long narrow seats associated with perineal pressure and reduced blood flow)
- Drugs and medications; birth control pill
- Spinal cord injury (can cause nerve damage; paralysis)
- Surgery (of or near reproductive-urinary system or abdomen; may damage nerves)
- Urinary incontinence (can cause embarrassment, avoidance)
- Vaginal atrophy
Antidepressants and benzodiazepines (fluoxetine, Prozac®, alprazolam, Xanax®) used to treat depression and anxiety are the drugs most commonly associated with loss of libido and inability to achieve orgasm. Buproprion (Wellbutrin®, an antidepressant) is sometimes prescribed for those who experience drug-related loss of sexual desire. Some evidence suggests that it restores libido. Chemotherapy drugs used to treat cancer are also associated with a lack of sexual interest. Some evidence suggests that extended use of birth control pills leads to reduced libido. Spinal cord injury, pelvic trauma, and other conditions that affect the peripheral nervous system, such as diabetes, can impair genital sensitivity, as can surgery involving the pelvic floor, bladder, abdomen, and genitals.
A third perspective, what could be called the dissatisfaction theory, is neither psychological nor medical. A great deal of women's sexual dysfunction is not caused by hormone deficiency or diminished pelvic blood flow; it results from inadequate genital stimulation. The fact that young, healthy women experience sexual dysfunction gives credence to this view. Poor communication by both partners may result in men not knowing how to stimulate a woman so that she becomes aroused. This leads to unsatisfactory sex and can cause arousal problems, lack of sexual interest, depression, and aversion to sex. Interestingly, the APA lists the "adequacy of [female] sexual stimulation" as a factor only in its discussion of female orgasmic disorder. This implies that it is not a fundamental aspect of female sexual function and so not affected by medical or psychological conditions.