Throughout its history, one of the most fascinating topics of psychiatry has been that of the causes and consequences of mental disorders. The desire to strengthen the reliability of diagnosis in this area has led to significant advances in two important fields: psychopathological description and the formulation of an integral diagnosis. Classifications allow the definition of categories and in the case of the two most read taxonomies in the field of mental health, Diagnostic and Statistical Manual of Mental Disorders (DSM) and the International Classification of Diseases (ICD), these provide the most commonly used criteria for diagnosis. The revised fourth edition of the DSM is now insufficient to cover the ever greater clinical challenges and research. For over ten years, work has been carried out on the structure of DSM-V (the fifth edition), but despite the planning, organization, prediction, and the contributions of guest experts, it is feared that all the requirements of modern psychiatry will not be met. The first edition of DSM was published in the 1950s. It was based on the terminology developed by William Meninger. This version of the manual and the following, published several years later, reflected the psychodynamic psychiatry which prevailed at the time. The third edition was published in 1980 and its revised edition seven years later. The emphasis here was on descriptive and syndromatic considerations. The fourth edition appeared several years later. The most striking change in this edition was the inclusion of variables resulting from empirical studies. A later edition was published in the year 2000. The first attempts to put together DSM-V started in 1999. From 1999 until 2007 work was done on the planning of the investigation and technical documentation of DSM-V and the inclusion of the so called investigation schedules. The second phase of the project, known as the refinement of the research program for DSM-V, was carried out between 2004 and 2007. A pilot test was undertaken between January and May 2010, among different segments of the population and different settings, to evaluate the revisions proposed by the working teams. Between March and April 2011, as a result of the field tests, the proposed criteria for diagnosis were reviewed. The dimensional measurements and the criteria for diagnosis will be reviewed again during the rest of 2011. The year 2012 will see the preparation of the final version of the text, and finally, in May 2013, DSM-V will be presented at the annual meeting of the American Psychiatric Association in San Francisco, California. Several external and independent authors have offered numerous proposals on topics related to psychopathology in general to the working groups formed for the preparation of DSM-V. Only some of these are mentioned below. One of the first factors to be taken into consideration in the revision of the manual is the need to distinguish between empirical questions or approaches and those of a more conceptual or philosophical nature, which should, by no means, be excluded. Another point to be evaluated is the advisability of defining phases according to the development of the condition, which would ideally create a schema focused on prevention. One of the expectations of psychiatry is that eventually laboratory criteria of diagnosis could be established, which could be measurable and would lead to clear statistics of psychiatric pathologies. As far as somatomorphic disorders are concerned, many practitioners agree that the current terminology and the systems of classification are inaccurate. One proposal is that this category should be eliminated altogether and that diagnoses should be made using an additional multidimensional description. One of the most interesting features of DSM is that it has had to accommodate changes brought about by new technologies. These advances go hand in hand with a new series of pathologies which need to be classified, as is the addiction to Internet. Undoubtedly, one of the greatest dilemmas facing DSM is how to classify eating disorders, as many people feel that the rather simplistic distinction between nervous anorexia and bulimia is not altogether convincing. There are two interesting proposals to consider in DSM-V: one is known as night eater syndrome and obesity, as in this case there is a compulsive consumption of food and an inability to limit this intake, in spite of a desire to do so. With regard to the compulsive, obsessive disorder, most experts believe that it is necessary to see the disorder as a spectrum, but defining criteria. Undeniably, a grave current problem which makes no distinctions is suicide. Different researchers recommend that suicidal behavior be considered and documented as a separate diagnosis in a sixth axis of the multioxis schema. Another important aspect concerns the giving of quality attention to patients. This has led to the proposal to expand DSM-V to include indicators for situations which could eventually be a cause for treatment. The proposal is to structure something different from what can be found in axis IV. In the case of paraphilias, it is deemed necessary that DSM-V should deal not only with the strictly descriptive aspect, but also with the semantic and linguistic. The importance of post-traumatic stress has been described, but there exists the doubt whether it is necessary to experience an adverse incident for this to be triggered. There has been a suggestion that the term "pre-traumatic" stress disorder be included in DSM-V to diagnose this condition. In the case of anxiety disorders, some authors advise the creation of a category known as "disorders caused by stress and fear", which would allow linking the diagnostic classification with etiology and thus define a "true" anxiety nosology. It would be advisable that the DSM-V included a category for "seasonal affective disorder" as such, and not simply as a variant in the "specification of the seasonal pattern" of depression. In the field of substance consumption, it has been argued that it is necessary to establish a classification which is not only categoric but also dimensional so as to improve its taxonomic usefulness. The organization of mental disorders in DSM-IV-TR and ICD-10 (tenth edition) is complex and this has led to exploring the feasibility of developing a meta-structural system of classification based on risk and clinical factors. For disorders originated in infancy, childhood and adolescence, it has been suggested that the disorder known as "temperament disorder by disphoria" be included in the forthcoming taxonomy, as well as the use of the terms insensitive/emotionless for behavioral disorders, among others. In the case of attention deficit hyperactivity disorder (ADHD), the current criteria are considered insufficient and it has been suggested that the starting age for this disorder be increased from 7 to 12 years of age. It is suggested that autism be considered autistic spectrum, thus eliminating the other disorders covered in this section, including Asperger syndrome. The question as to whether this taxonomic-diagnostic system, to be implemented world-wide, will be both valid and reliable enough to cover all variations and particular characteristics of different cultures, ethnic groups, social groups and geographical regions in Mexico is another matter of concern, due to the lack of tools available for daily clinical work, except for the International Classification of Diseases of the World Health Organization. There are, at present, a number of doubts and queries which will need to be laid open and evaluated in all seriousness in order to obtain concrete and integral answers, given that the manual will continue to be used for clinical purposes in different parts of the world. The challenge will be to find the best way to apply diagnostic criteria, avoiding omissions and oversimplifications and taking into account the cultural and social context worked in.