Sexual Dysfunctions

Sexual Response Cycle

The fundamental diagnostic categories of sexual dysfunctions reflect the traditional view of the four-phase model of human sexual response. This model, which is based on sexual response more characteristic of men than women, assumes a linear progression of relatively discrete phases. The cycle begins with an initial awareness of [Page 1458]sexual desire (i.e., yearning for sex and thinking or fantasizing about it) that leads to the arousal (excitement) phase. The arousal phase is characterized by increased blood flow to genital tissues that produces vaginal lubrication in women and erection in men. This phase may lead to the reflex rhythmic muscular contractions of the orgasm phase that release muscular tension and blood from the engorged blood vessels. In the resolution phase that follows, the physiologic changes that took place during the preceding phases are reversed and the body returns to an unaroused state.

Contemporary research suggests that women's sexual response is more complex than is indicated by this model, and involves overlapping phases of sexual response in a variable sequence, particularly when engaged in a long-term relationship. In the initial phase of a relationship, women typically experience relatively high and spontaneous sexual urges. At later stages of a relationship, when couples are more likely to experience habituation to sex and tend to show lower levels of sexual intimacy (e.g., engagement in foreplay, expressing signs of affection), women's sexual desire, which is more affected by relational context than men's, may become a responsive rather than a spontaneous event. As such, at the beginning of a given sexual interaction, a woman may not necessarily sense sexual desire per se, but rather be motivated to engage in sex for other reasons (e.g., promoting her sense of closeness, pleasing her partner, obtaining relief from stress). Then, when a woman is willing to become sexually receptive, she may consciously focus on sexual stimuli and feel sexually aroused. This subjective sense of arousal may, in turn, trigger the desire for sex itself (i.e., responsive sexual desire). If the sexual stimulus is perceived as effective and the woman can stay focused long enough, she may experience sexual satisfaction (with or without orgasms).

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