On the one hand, the constellations of causes and the phenomenology of the disorders are clearly different, but on the other hand, the patients' self-experience and the nature and content of their problem reports are often uniform and similar. For most patients, the erectile failure itself and the associated feelings of anxiety, embarrassment, shame, despair, anger, and disappointment are at the forefront of their experience. Although the way in which these feelings are dealt with varies from individual to individual, the effects of repeated or chronic erectile dysfunction on the mental and physical well-being of the man are almost always far-reaching and very stressful. The man's self-esteem, which is to a large extent linked to sexual functioning and potency, is regularly and usually considerably reduced. There may be pronounced withdrawal and avoidance tendencies, which in turn, like the disorder itself, can put a strain on the partner relationship, lead to social or professional difficulties, depression, or other psychological or psychosomatic complaints.
Since men's sexual standards are still, and now even into older age, characterized by a pronounced need for performance and by the myths and distortions of the “porn model” of sexuality , the erectile dysfunctional man feels hopelessly behind in relation to this image, as a failure and a “looser”. In men who are in committed partner relationships, the balance, the sexual equilibrium of the couple shifts , even if the partner is understanding and cooperative. In men without a steady partner, there is often a feeling of not being able to enter into a new partner relationship, since one would not be able to meet the woman's sexual demands anyway and would feel like a “cheater” towards her.
The feelings described above, and the vicious circle triggered by erectile dysfunction are so powerful that many men are unable to access the underlying causes of their problems. In clinical practice, it is always striking and sometimes downright astonishing that patients do not want to or are unable to establish any relationship between stressful life events or serious personal or partnership conflicts or crises and their sexual problems, while this connection is virtually obvious to the physician. If the patient is confronted with this discrepancy, the stressful factors are not infrequently trivialized, and it becomes clear that the man expects his functional capacity, his penis, to be “immune” to external influences and to function automatically.
The sex therapist Zilbergeld also points out this fact and goes even further when he says that many men want to make their penis work by a kind of “cold start” and block out the fact that an erection has something to do with sexual arousal, intimacy, security, and the fulfillment of certain personal needs and conditions . Numerous patients in our consultation even report that they are not actually concerned with their sexuality and sexual pleasure, but are here to be enabled to satisfy their partner's sexual needs and desires again. Finally, the experience that the majority of patients are convinced of a somatic cause of their erectile dysfunction fits this picture and not infrequently react with disappointment or disbelief when organic diagnostics have not produced any findings. A physical cause fits better into the concept of “psychological automatism” of sexual functioning, promises a less costly treatment, and is linked with the hope of not having to deal with psychological or partner conflicts.
In accordance with the division of the symptomatological appearance of erectile dysfunctions mentioned at the beginning, this disorder actually presents itself as very heterogeneous and diverse for the clinically active physician or psychologist. Thus, erectile dysfunction problems differ on the basis of a number of very different dimensions that must be taken into account for diagnostic assessment. One question, which is only banal at first glance, concerns the issue of whether erectile dysfunction is actually at the forefront of the issues. In a number of patients, the sexual dysfunction consists wholly or predominantly of ejaculatio praecox, and it is not uncommon to see patients in whom a reduction in appetence is at the center of the problem, but this is almost never seen as a core difficulty by the men concerned themselves.
Besides the dimension of the type of disorder, the symptomatology is decisively characterized by the so-called formal descriptive features, which alone can provide a good diagnostic guide for a disorder history. Erectile dysfunction can be differentiated according to 3 formal criteria, namely:
Although etiological categorization based on analysis of symptomatology alone is possible in a number of cases, it should generally be undertaken only after more detailed assessment and diagnosis, which is comprehensively described in this book. Following a suggestion by Levine , a rough classification into 4 “generic types” of erectile dysfunction can be made, taking into account the dense interaction of somatic and psychological factors:
This rough classification must then be further substantiated and differentiated by identifying the specific effective causes, integrating 3 groups of data:
Thus, the basic clinical process includes 3 stages:
This not only allows the patient's individual disorder pattern to be precisely determined, but in most cases also allows a suitable treatment plan to be drawn up.
The question of the frequency of a particular disease is significant in many respects, including for purposes of legitimizing one's own actions, for health policy considerations, for justifying increased research efforts, for attracting third-party funding or grants, etc.
For the patient, it can mean a certain relief to learn that very many men are affected by the same problems. 1.2 Epidemiological data 7 When considering the relevant figures, the prevalence of erectile dysfunctions in the general population must be distinguished from figures collected on the basis of clinical samples, which characterize the proportion of various disorder patterns among the clientele of different professional institutions. Regarding the prevalence of sexual dysfunctions, for decades the results of the famous Kinsey studies from the 1940s were the only reliable sources of data. In Kinsey's sample, the prevalence of erectile dysfunction was less than 1% in those under 30 years of age, less than 3% in those under 45 years of age, just under 7% in those 45–55 years of age, 25% in those 65 years of age, and up to 75% in those 80 years of age, although the representativeness of the Kinsey data is limited due to the small number of respondents in those over 55 years of age . Spector & Carey  examined a total of 23 studies on the prevalence of sexual dysfunction in 1990 and found prevalence figures ranging from 4% to 9% for erectile dysfunction. Lendorf  surveyed a group of 272 Danish men aged 30–79 years for various dimensions of erectile failure and found impotence (defined as inability to initiate or complete sexual intercourse) in a total of 4% of his samples, 11% in those over 60 years of age, and 10% in those over 70 years of age; a subjective sense of erectile insufficiency relative to their age group was present in the remaining 20%. In a study of 331 Dutch men aged 20–65 years, Diemont  found 2.7% erectile dysfunction in the entire sample.
The most frequently cited and productive recent study of the prevalence of erectile dysfunction is the Massachusetts Male Aging Study (MMAS ), a large-scale study of the relationship between age and health in men, in which various items of a questionnaire related to sexual activity and function were answered by 1290 men. A “calibration sample” of 303 erectile dysfunction patients examined in a urology clinic was used to calculate the degree of erectile dysfunction in the main nonclinical sample. The results showed that 52% of 40- to 70-year-olds had at least mild erectile dysfunction, with 17% having minimal impotence, 25% having moderate impotence, and 10% having complete impotence. The MMAS results confirmed the strong age dependence of erectile dysfunction: between the ages of 40 and 70, the percentage of complete impotence tripled from 5% to 15%, the likelihood of moderate impotence increased from 17 to 34%, whereas the percentage of minimal impotence remained constant at 17%. Only 32% of 70-year-olds described themselves as free of erectile dysfunction. In the data controlled for the age factor, significantly higher percentages of complete erectile dysfunction were seen in men receiving treatment for diabetes (28%), heart disease (39%), and hypertension (15%) compared with the overall sample (9.6%). Correspondingly, percentages for complete impotence were also significantly elevated in men taking hypoglycemic agents (26%), antihypertensive medications (14%), vasodilators (36%), and cardiac drugs (28%). From their data, the authors calculated that approximately 18 million U.S. men aged 40–70 years suffer from erectile dysfunction, which is therefore a serious and quantitatively significant health problem. 8 Chap. 1 Symptomatology and epidemiology of erectile dysfunctions If one tries to transfer these data to German conditions, one would have to assume figures that are likely to be between 4 and 6 million of all men.
In the final consideration of some figures, which were collected on the basis of clinical samples and allow statements on the use of professional help and on the distribution of the various disorder patterns, it is important to note the marked difference, especially in the case of sexual dysfunctions, between a condition complained of as a problem and a disorder for which professional help is actually sought. This discrepancy is considerable in erectile dysfunction, but even more pronounced in ejaculatio praecox. In a Danish study  of men around 50 years of age, 40% reported sexual function issues of various kinds, but only 7% found these difficulties unusual for their age, and only 5% were willing to seek treatment. In interpreting these data, we are largely left to conjecture; ranging from the assumption that erectile dysfunction is an under-diagnosed and under-treated health problem  to the hypothesis that many men and their partners manage to come to terms with minimal or moderate impairment in sexual function. Figures from the United States on the use of professional help show that 1 985 525 000 outpatient physician contacts were billed for erectile dysfunction, which was 0.2% of all outpatient physician visits. Based on these figures and the MMAS prevalence data,  it appears that between 2.6 and 5.2% of affected men seek professional help annually. Finally, it can be inferred from various publications that erectile dysfunction accounts for the highest proportion of male disorders, and often of male and female disorders as a whole, in specialized treatment facilities for the diagnosis and treatment of sexual disorders [n]. In the sexual outpatient clinic of the Hamburg Department of Sexual Research, erectile dysfunction was the most common symptom among male advice-seekers in both the mid-1970s and the early 1990s, accounting for 67% and 60%, respectively ; erectile dysfunction was also the most common main symptom in the sexual medical consultation of the University Hospital of Zurich, accounting for 46%, followed by ejaculatio praecox, accounting for 34% . All data available today thus suggest that erectile dysfunction is very common in the general population as well as in the clinical setting, and is indeed a significant health problem.