Vol 5 n° 2 - Psychiatric disorders in somatic medicine
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In  the  last  few  decades,  the  traditional  separation between mental and somatic disorders has been increas- ingly abandoned. This idea probably originated from the French philosopher Descartes who, for religious reasons, was unable to examine the brain directly, with the conse- quence that mind and body were considered as distinct entities. We are now aware that the spectrum of mental disorders described in the ICD-10 (International Classifi- cation of Mental and Behavioral Disorders) and the DSM- III/IV (Diagnostic and Statistical Manual of Mental Disor- ders, Third and Fourth Editions) are frequently associated with somatic disorders such as diabetes, hypertension, and cardiovascular disease. Various factors are most prob- ably  involved.  According  to  psychosomatic  theories, somatic disorders are related to psychological problems. On the other hand, according to the symptoms they pro- duce, eg, pain, or when they are life-threatening, somat- ic disorders may precipitate or exacerbate psychopatho- logical symptoms. This kind of comorbidity is only part of the focus of this issue. Recent achievements in modern methodology (a better recognition of disease, epidemiol- ogy, molecular biology, and genetics) have helped our understanding of these problems. Common factors may predispose to somatic and mental disorders, simultane- ously leading to true comorbidity. (Comorbidity is also sometimes an artifact of our classification systems [see Dialogues in Clinical Neuroscience, 1999, volume 1, No. 3 entitled Nosology and Nosography].) Treatment can itself produce adverse side effects, leading to either somatic or psychiatric symptoms. The articles in this issue cover some of these aspects. The State of the art article is dedicated to psychiatric epi- demiology, illustrating the current status and the pitfalls of such studies in primary care. Structural issues and vari- ations between health care systems in different countries allow only a rough estimate of the occurrence of mental disorders in primary care. The question of what “a case” is can be considered to be a key problem. The modern classification systems strictly demand a certain number of symptoms, episodes, or duration of illness. If such criteria are not fulfilled, a diagnosis cannot be made. Even after diagnosis, it is not clear which treatment would be appro- priate and how long it should be prescribed for. There remain many unresolved questions. Hans-Ulrich Wittchen, Stephan Mühlig, and Katja Beesdo (page 115) present the epidemiological data showing the high number of men- tal disorders in primary care (up to 30%) and extensively discuss the problem. Two Basic research papers provide insights into molecular genetics and immunological aspects of mental and some somatic disorders. Brigitta Bondy (page 129) describes some common genetic risk factors for a variety of both psychiatric and somatic disorders. Dysregulation of the hypothalamus-pituitary-adrenal axis may account for many disturbances. Alterations in neurotransmitters or cytokines are other candidates for involvement in many somatic symptoms and behavioral abnormalities. Migraine and fibromyalgia are examples of such comorbidities. The relationship between genotypes, ie, variations in genes and phenotypes, is also mentioned. The association of depression and cardiovascular disorders based on com- mon genetic risk factors is comprehensively discussed. The serotonin transporter, G-protein, and the angiotensin-con- verting enzyme are examples of such candidate genes. Considering that most of these disorders have a multifac- torial etiology and that they have an oligogenic or poly- genic inheritance, such studies mark the beginning of a new era in medicine. The second Basic research paper was written by Markus J. Schwarz (page 139), who gives an overview on our cur- rent knowledge on how, and in which way, the immune system interacts with the brain. The field of so-called “psychoneuroimmunology” has seen enormous progress in recent decades starting from rather anecdotal reports mostly  in  psychosomatic  medicine.  This  discipline  is becoming increasingly accepted as an exact science. The number of publications has increased remarkably in the last few years, and its importance has been recognized by the Immunology and Psychiatry Section of the World Psy- chiatric Association (WPA) and other international orga- nizations. Markus J. Schwarz gives an introduction on how products of the immune system (the cytokines) inter- act in a bidirectional manner with the brain. The effects of major cytokines are described in this first part of the paper, while the second part focuses on psychiatric symp- toms and disorders. The main current theories related to the pathophysiology of major depression and schizophre- 1 1 3 I n   t h i s   i s s u e . . .