The diagnosis of premature ejaculation

There is increasing interest in the management of premature ejaculation (PE), including the search for improved pharmacological approaches triggered by the potentially very large marketing opportunity. Just how large the market may be is difficult to predict. Estimates are based on epidemiological findings, but prevalence figures vary greatly depending on the operational definition of PE used in the questionnaires employed in their generation. Numerous definitions and diagnostic criteria have been used. However, there can be little doubt that PE is the most frequent sexual symptom among men (1). Masters and Johnson considered a man to have PE ‘if he can not control his ejaculatory process for a sufficient length of time during intravaginal containment to satisfy his partner in at least 50% of their coital connections’ (2). They do not define partner’s satisfaction, but many workers consider it to mean orgasm attainment (3). However, almost a third of women report inability to experience orgasm (4). Furthermore, a woman who dislikes intercourse might be highly satisfied if it lasts only a very short time. Hence, for these reasons, Masters and Johnson’s definition of PE is not valid. For similar reasons, the World Health Organization’s definition of PE (‘the inability to control ejaculation sufficiently for both partners to enjoy sexual intercourse’) (5) is also unrealistic. Whilst Masters and Johnson, the WHO and many other workers include partners’ wishes or behaviour in the diagnostic criteria for PE, The American Psychiatric Association includes the issue of distress; ‘Persistent or recurrent ejaculation with minimal sexual stimulation before, on, or shortly after penetration and before the person wishes it. The disturbance causes marked distress or interpersonal difficulty’ (6). The inclusion of distress is important. Although recent research has shown that PE is associated with reduced sexual satisfaction and increased distress and interpersonal difficulty (7) other research suggests that not all men who ejaculate rapidly are distressed by it; nor are their partners. In a Swedish study only 49% of men who reported ejaculating soon after intromission considered it a problem and only 38% of women considered it a problem (8). In determining whether a patient meets their diagnostic criteria for PE, the American Psychiatric Association tells clinicians to take into account factors that affect duration of the excitement phase [of the sexual response], such as age, novelty of the sexual partner or situation, and recent frequency of sexual activity (6). Hence, application of the diagnostic criteria requires considerable knowledge of the psychophysiological factors that influence ejaculatory activity. Clinicians untrained in sexual dysfunction may not have such knowledge and may judge a patient’s ejaculatory function in comparison to their personal experience, their expectation of normality or rely entirely on the patient’s self diagnosis of ejaculating too quickly. However, many patients have unrealistic expectations as illustrated by the results of a survey involving over 7000 men who were asked if they ejaculate too soon after penetration or find that they are not able to continue intercourse as long as they think they should or would like to (9). About 70% of respondents said that they did but when asked how long they mean, 17% gave the time as over 5 min and 1% gave 90 min! In another study of 152 highly educated heterosexual couples, men’s and women’s mean ideal duration of intercourse was 18.45 and 14.34 min, respectively, whereas their actual ‘performance’ was shorter (mean, men 7.86; women 7.03 min) (10). The time interval between penetration and ejaculation is known as the intravaginal ejaculatory latency time (IELT). This is measured by a stopwatch, usually operated by the female partner. In a multinational population study involving 500 heterosexual couples, in stable relationships of at least 6 months’ duration who were having regular sexual intercourse, the IELT was positively skewed and ranged from 0.55 to 44.1 min (median 5.4) (11). The IELT decreased significantly with age, with the median decreasing from 6.5 min in the 18to 30-year age group to 4.3 min in men over 51 years. Based on these normative data and using a currently accepted epidemiological definition of a disease or disorder (i.e. clinical symptom with a population prevalence of less that two standard deviations below the mean), Waldinger et al., in considering lifelong PE, propose that men with IELT of less than 1 min have definite PE whilst men with IELT between 1 and 1.5 min have probable PE (12). In clinical trials on PE pharmacotherapy it is essential to have a tight definition of PE, perhaps using the IELT criteria mentioned above. IELT can also provide There can be little doubt that PE is the most frequent sexual symptom among men 12 Editorials