The definition of premature ejaculation is imprecise and the subject of disagreement among sex therapists and researchers. Masters and Johnson suggested that ejaculation occurs prematurely if the woman does not reach orgasm during intercourse at least 50 percent of the time. This definition is problematic, as some women reach orgasm very rapidly during intercourse, while for others, orgasm never occurs during intercourse, regardless of duration. Kaplan proposed that a lack of voluntary control over the occurrence of orgasm defined premature ejaculation. However, it is not clear that the ejaculation reflex is truly subject to voluntary control. Rather, the ejaculation reflex, similar to the sneezing reflex, is at best only partially under voluntary control. The Diagnostic and Statistical Manual of the American Psychiatric Association defines premature ejaculation as "ejaculation with minimal sexual stimulation or before, upon, or shortly after penetration and before the person wishes it." This definition acknowledges that there must be a subjective element to the diagnosis of premature ejaculation. As well as considering the duration of intercourse, the nature of the couple's sexual interaction must be evaluated. A couple who engages in 45 minutes of unrestrained manual and oral-genital foreplay, followed by one minute of pleasurable intercourse, would not be considered to be troubled by premature ejaculation. However, ejaculation after ten minutes of intercourse might be premature if this duration can only be achieved by avoiding all foreplay; spraying the penis with a skin anesthetic; wearing three condoms; thinking unpleasant, distracting thoughts; and biting one's tongue so the pain interferes with sexual arousal. The rates of premature ejaculation found in population studies have varied between 10 percent and 25 percent of men surveyed, probably due to differences in the definition of the problem. In terms of actual duration of intercourse, the 1948 Kinsey Report found that "for perhaps three-quarters of all males, orgasm is reached within two minutes" of intercourse, but Hunt's 1974 study found that the average duration of intercourse had increased dramatically, to 10 to 14 minutes, in the intervening 26 years. This dramatic change in the societal norm for duration of intercourse has increased the distress of men who suffer from premature ejaculation. Premature ejaculation, according to Bancroft, is typically a younger man's problem, with the majority of cases involving men under the age of 30. Premature ejaculation is typical for young men in their first sexual experiences and might be considered normal at this time. However, as these men have no history of successful sexual relationships as a basis for their sexual self-esteem, self-blame and self-labeling as dysfunctional often occur. With continued sexual experience, most men spontaneously get over their initial premature ejaculation. Along with the effects of experience, as a normal physiological change in aging the time required for a man to reach orgasm increases, but this is a slow change occurring over many years. A young man whose premature ejaculation is not resolved with greater sexual experience would have to wait 20 or 30 years for normal aging processes to solve his problem. Premature ejaculation does not seem to be caused by any physiological factors or medical conditions. While Kaplan suggested that some local diseases or medications could cause premature ejaculation, Bancroft did not find this to be the case. Research has also failed to connect premature ejaculation with the complex individual psychodynamic and couple-relationship problems associated with other sexual dysfunctions, such as hypoactive sexual desire. Rather, premature ejaculation seems to be typical of young, sexually inexperienced males who simply have not learned to slow down and modulate their arousal and to prolong the pleasurable process of making love. Men who have sex only infrequently are also prone to ejaculate prematurely. Indeed, Kinsey, Pomeroy, and Martin proposed that the primary cause of premature ejaculation was a low frequency of sexual activity. Research has indicated that sensory thresholds in the penis are lowered by infrequent sexual activity and that premature ejaculation patients have a low rate of sexual activity. However, it may well be that premature ejaculation makes sex an unpleasant failure experience, which is therefore avoided, rather than that low frequency of sexual activity causes premature ejaculation. Anxiety and ejaculation both involve activation of the sympathetic nervous system, so anxiety about trying to delay ejaculation can make the problem worse. Masters and Johnson proposed that men learn to be rapid ejaculators during adolescent masturbation, when they often hurry to ejaculate because of fear of being discovered by parents. However, such experiences seem to have been equally common in men who are not premature ejaculators. There has even been some speculation by evolutionary biologists that rapid ejaculation may have been selected for during primate evolution, through a "survival of the fastest" process. A male who could ejaculate rapidly would be more likely to reproduce successfully, as there would be less chance of the female escaping, another male interrupting, or a predator attacking before coitus was completed. Kaplan proposed that premature ejaculators cannot accurately perceive their own arousal level and therefore cannot engage in self-control. However, one laboratory study comparing premature ejaculators and age-matched normal control subjects actually found that the premature ejaculators were more accurate when their self-ratings were compared to objective measures of physiological arousal. It may be that premature ejaculators, who because of their problem keep their attention focused on how close they are to ejaculation during sexual activity, have trained themselves to be unusually accurate self-observers of arousal. None of the theories of the cause of premature ejaculation is well supported by research, except that premature ejaculation is typical of younger, less experienced men and men who have sex infrequently. The treatment of premature ejaculation, using the "pause" and "squeeze" procedures developed by Semans and by Masters and Johnson, has been found to be highly effective. Research has demonstrated that such procedures work well in group as well as in individual treatment, and in self-help programs; they can be practiced in individual masturbation with relatively good transfer of therapeutic gains when sex with a partner is resumed. Success rates of 90 percent to 98 percent are reported. In the stop-start or pause procedure, the penis is manually stimulated until the man is fairly highly aroused. The couple then pauses until his arousal subsides, at which time the stimulation is resumed. This sequence is repeated several times before stimulation is carried through to ejaculation, so the man ultimately experiences much more total time of stimulation than he ever has before and thus learns to have a higher threshold for ejaculation. The squeeze procedure is much like the stop-start procedure, with the addition that when stimulation stops, the woman firmly squeezes the penis between her thumb and forefinger, at the place where the glans of the penis joins the shaft. This squeeze seems to further reduce arousal. After a few weeks of this training, the necessity of pausing diminishes, with the man able to experience several minutes of continuous penile stimulation without ejaculating. Next, the couple progresses to putting the penis in the vagina but without any thrusting movements. If the man rapidly becomes highly aroused, the penis is withdrawn and the couple waits for arousal to subside, at which point the penis is reinserted. When good tolerance for inactive containment of the penis is achieved, the training procedure is repeated during active thrusting. Generally, two to three months of practice is sufficient for a man to be able to enjoy prolonged intercourse without any need for pauses or squeezes. We have no real understanding of why the pause and squeeze procedures described by Semans in 1956 and Masters and Johnson in 1970 work. The pause procedure fits Guthrie's theoretical paradigm for counter conditioning by "crowding the threshold." Additionally, the stimulation and pause procedure is typically repeated by the patient several times per week, thus raising the frequency of sex and raising the sensory threshold of the penis. Either or both of these mechanisms may underlie the effectiveness of treatment. Some variations on the pause and squeeze procedures have been reported, typically as clinical case reports. One variation described by LoPiccolo involves reversing one of the physiological changes that occurs during high arousal. During high arousal, the scrotum contracts and elevates the testes close to the body. As well as having the patient cease stimulation or squeeze on the penis, the patient may also be instructed to stretch out the scrotum and reverse this testicular elevation. However, during high arousal, any additional stimulation of the scrotum and perineum may trigger an ejaculation and thus may make the pause and squeeze procedure ineffectual. Empirical data on the effectiveness of this technique are lacking. Segraves reported that drugs and medications that block sympathetic arousal often have the effect of delaying ejaculation. Such agents include anti-anxiety, antidepressant, and major tranquilizing medications; sedatives; some medications used to treat high blood pressure; and some antihistamines. However, because of serious side effects, the use of medication in treating premature ejaculation is not recommended, especially when the effectiveness of the behavioral retraining procedure is considered. Many of the recreational or "street" drugs such as alcohol, marijuana, cocaine, "downers" (barbiturates), and heroin also delay ejaculation, and although some men do use such agents to deal with their premature ejaculation, this is even more unwise than the use of prescription medications. It is somewhat puzzling that although there is little agreement about the definition or cause of premature ejaculation, and no real understanding of how the treatment procedure works, treatment is virtually 100 percent effective. If one has to have a sexual dysfunction, this is the one to have.   REFERENCES Bancroft, J. Human Sexuality and Its Problems. New York: Churchill Livingston, 1989. Frank, E., C. Anderson, and D. Rubinstein. Frequency of Sexual Dysfunction in "Normal" Couples. 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