Prevalence and depression statistics in different countries of the world

In recent years, depression is considered around the world as one of the main causes of decline and disability. By the share of lost for a full-fledged life of years, it is depressive disorders that outstrip all other mental illnesses, including such as Alzheimer's, alcoholism and schizophrenia. Depression ranked fourth among all diseases for integrative burden assessment, which is borne by society in connection with them. Thus, A. Nierenberg (2001) notes that in America about 6 million people suffer from depression every year, and their treatment costs more than 16 billion dollars. By 2020, according to this criterion, depressive disorders will take second place, second only to coronary heart disease.

Hence it is clear that the development of effective methods of therapy and prevention of depressive disorders is one of the most important tasks of modern psychiatry. It is no exaggeration to call this task the cornerstone of mental health care in the 21st century. Solving such a complex problem requires consideration of various factors contributing to the occurrence of depressions that affect their course, determining their prognosis and the effectiveness of treatment. Among these, certainly, are ethno-cultural factors, whose role in the etiopathogenesis of depressions is recognized today by virtually all researchers. In particular, American psychiatrists LJKirmayer and D.Groleau (2001) argue that the presence of ethnographic knowledge is a prerequisite for understanding the causes, theology and the course of depressive disorders.

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The current state of research of depressive disorders

As already noted, in recent decades, the worldwide trend is to increase the incidence of the population with depressive disorders. According to the WHO-sponsored epidemiological studies, built on a random sample of patients in the general health network in 14 countries, the average prevalence of depression in the last decade of the 20th century, in comparison with the 60th years (0.6%) was 10.4%. Thus, over the past 30 years, the number of patients with depressive disorders has increased more than 17 times.

The prevalence of depression in the primary care system (according to WHO)

A country	Depressive disorders,%
Japan	2.6
India	9.1
China	4.0
Germany	11.2
Nigeria	4.2
France	13.7
Turkey	4.2
Brazil	15.8
Italy	4.7
Netherlands	15.9
USA	6.3
England	16.9
Greece	6.4
Chile	29.5
Average	10.4

Given that the detection and clinical qualification of depressive disorders were carried out within the framework of a single program based on common methodological and clinical diagnostic criteria and using a common tool, a significant (by a factor of 10 or more) variation in prevalence rates of depression in different countries of the world: from 2.6% in Japan to 29.5% in Chile. At the same time, it is difficult to single out these or other regularities of the differences. One can only cautiously say about the tendency of the lower prevalence of depressive disorders in Asian, African and North American countries, as well as in the countries of the South of Europe and greater in Western Europe and Latin America. As for the levels of socio-political stability and economic development of the analyzed countries, there is no correlation between the prevalence of depressive disorders and these indicators. The data obtained may indicate a certain role of the proper ethno-cultural factors in the origin and prevalence of depressive pathology.

Many researchers believe that the real figure of the prevalence of depression can be even higher if we take into account the cases of so-called depressive disorder disorders-some forms of pathology of drives, dependence on alcohol and psychoactive substances, somatoform, psychosomatic and neurotic disorders that occur with depressive symptoms.

Thus, according to the results of a US-wide, unmarked survey of 226 people in general health care facilities, 72% of them showed signs of unexpressed depression observed for 4 weeks - depressed mood, cognitive impairment and individual vegetative manifestations. In the corners of them, a major depressive disorder was noted in the anamnesis, with almost a half of the cases showing a hereditary burden of unipolar depression. Proceeding from this, the authors made the following conclusions:

1. in the clinical picture of unexpressed depression, low mood, disturbances in the cognitive area predominate, and vegetative symptoms are much less common;
2. Depressive depression can occur either as an independent disease or as a stage of a recurrent unipolar depressive disorder;
3. Depressive depression should be considered within the continuum of "clinical seriousness".

According to domestic researchers, in Russia, about half of those who apply to territorial polyclinics have some signs of depressive disorders. The prevalence of mild depressive disorders, mixed anxiety-depressive states and their occurrence in somatic diseases are even greater.

The clinical structure of depressions, first detected in patients with a general-purpose network, according to the results of a study conducted in Moscow MN Bogdan (1998): depressive episode - 32.8%, recurrent depressive disorder - 29%, chronic affective disorders, including cyclothymia and dysthymia - 27.3%, bipolar affective disorder - 8.8% of cases.

Almost all researchers recognize the role of age and sex in the occurrence and prevalence of depressive disorders. According to WHO (2001), depression most often develops in adulthood. At the same time in the age group of 15 years - 44 years, these disorders are the second heaviest burden, accounting for 8.6% of the number of years of life lost as a result of disability. In addition, there is information in the literature about the existence of ethno-cultural differences in relation to the age preferences for the onset of depressive conditions.

Thus, if in some African countries (Laos, Nigeria) there is a predominance among people with depressive disorders of adults aged 30-45 years, in the United States these diseases most often develop in "adult adolescents". In confirmation can be given the data of the analytical review of PI Sidorov (2001), from which it follows that 5% of the population aged 9 to 17 suffer from depression in the United States, and 10% of the total number of schoolchildren in Ehmre. In most European countries, the highest prevalence of depressive disorders is found in the elderly. This is due to the accumulation of life difficulties inherent in this age and the reduction of psychological stability.

Sexual features of the prevalence of depression are reflected in WHO (2001), according to which the prevalence of depression in most countries of the world is higher among women. Thus, the average frequency of unipolar depressive disorder is 1.9% for men and 3.2% for women, and for the first time depressive episode - respectively 5.8 and 9.5%.

Among the social factors contributing to the development of depression, poverty and interrelated unemployment, poverty, low level of education, homelessness are highlighted. All these factors are the lot of a significant proportion of people in contrasting countries in terms of income levels. Thus, according to the results of transnational studies conducted in Brazil, Chile, India and Zimbabwe, depressive disorders are on average 2 times more common in low-income groups than among the rich.

According to the unanimous opinion of researchers, in all countries people with depressive disorders are at the highest risk of committing suicide. This aspect of the problem will be discussed in more detail in the relevant section of this book. Here we will limit ourselves to only some figures confirming the correctness of such a conclusion. According to the world literature, among all suicides, the proportion of people with depression is 35% in Sweden, 36% in the United States, 47% in Spain, and 67% in France. There is also information that 15-20% of patients with depression commit suicide.

Significantly less often in the literature information about the ethnocultural features of the clinical picture of depressive disorders. In this respect, comparative studies of clinical manifestations of depression in eastern and western cultures deserve attention.

Most authors note that in eastern cultures, depression is much more often somatized. VB Minevich (1995) and PI Sidorov (1999) came to the same conclusion in our country, who established accordingly that the Buryats and the small peoples of the North of Russia develop almost exclusively somatized depressions, which considerably complicates their timely detection and treatment . VBMinevich explained this phenomenon by the fact that complaints of the depressive spectrum (depressed mood, depression, depression) are absolutely non-normative in Eastern culture, to which Buryatia also belongs. Proceeding from this, depression in the eastern ethnoses initially acquire a somatized character.

The presented data are indirectly confirmed by the results of a number of foreign studies on chronic depressive disorder, dysthymia. It is commonly believed that the prevalence of this disease in different countries around the world is approximately the same and averages 3.1%. However, according to L.Waintraub and JDGuelfi (1998), in the countries of the East, corresponding figures are much lower, for example in Taiwan they are only 1%. However, it remains unclear whether dysthymia occurs in the East less often or is simply not recognized due to its somatization.

Thus, there are scientifically confirmed differences in the prevalence and clinical manifestations of depressive disorders in eastern and western cultures. In addition, there is information in the literature about the existence of "internal" (subcultural) differences in each of these cultures. This is the original work of the domestic researcher L.V. Kim (1997), who studied the clinical and epidemiological features of depression among teenagers of ethnic Koreans living in Uzbekistan (Tashkent) and the Republic of Korea (Seoul).

The author found that the prevalence of actively identified depressive disorders in the general population of Seoul teenagers (33.2%) is almost 3 times higher than in Tashkent (11.8%). This is a reliable indicator, since the study was carried out according to unified methodological approaches and was based on general clinical criteria.

According to LV Kim, the higher prevalence of depression among teenagers in South Korea is due to socio-environmental factors. In recent decades, the idea of the inextricable link between the prestigious position in society and higher education has been established in the country, so the number of entrants is many times higher than the number of places in universities, and the requirements for students are becoming increasingly high. Against this background, the so-called "pressure of success" is formed, manifested, on the one hand, by the adolescent's desire to achieve success and the desire to conform to the claims of the parents; on the other hand, the presence of fear, anxiety, the expectation of failure and failure. Because of this, "pressure of success" is becoming one of the most powerful risk factors for the development of depression among South Korean adolescents.

The author believes that additional arguments in favor of the depressogenic role of "pressing the success" in the contingent of teenagers in Seoul are:

1. a greater proportion of "depressed adolescents" of male representatives as a consequence of the traditional orientation for South Korea to achieve social and professional success by men;
2. dependence of depression on the presence of a chronic physical illness that prevents the achievement of social success and career aspirations of the adolescent;
3. significant (more than 2 times) prevalence of schoolchildren with high achievability among "depressed adolescents" in Seoul in comparison with the corresponding group of Tashkent, which reflects a higher level of socially determined claims in a competitive society.

As for other pathogenic socio-psychological factors, among depressed teenagers from Uzbekistan, compared to their peers from Seoul, interpersonal problems are significantly more often identified, including with parents (4.2 times), teachers (3.6-fold) , siblings (6 times), peers (3.3 times). This can be explained by certain subcultural differences between the metropolitan and diaspora representatives. In particular, unlike Uzbekistan in Korea, adolescents are brought up on the traditions of Buddhism, which condemn open manifestations of aggression and conflict. The analysis of other socio-demographic and socio-psychological factors did not allow to establish their significant connection with the formation of depressive disorders in adolescents both in Korea and in Uzbekistan.

Clinically, when studying depressive disorders in adolescents of the subpopulations compared, no ethno-cultural features and differences were found. The most frequent typological variants of depression are dull depression (28.4%), astenopathy (20.9%), anxiety (16.4%), psychopathic manifestations (13.4%), dysmorphophobic syndrome (11.9% %), with somatovegetative disorders (9%). According to the clinical criteria of DSM-1V, almost half of all cases were mild depressions (Mild) - 49.3%, followed by moderately severe depression (Moderate) - 35.1% and the smallest proportion accounted for pronounced depression (Severe) - 15 , 6%.

Thus, the prevalence, conditions of formation, clinical manifestations of depressive disorders can have not only ethnocultural, but also ethno-subcultural differences, knowledge of which is important for psychiatrists.

In the Russian psychiatry ethno-cultural studies of depressive disorders are very few. In this respect, we can note a cycle of comparative transcultural studies of depressions performed by OP Vertogradova and co-authors. (1994, 1996). In one of the works, the authors studied the cultural features of depressive disorders in the indigenous population of the Republic of North Ossetia (Alania). A feature of Ossetians is that, living in the North Caucasus, they do not belong to the peoples of the North Caucasian family. According to their ethnicity, Ossetians belong to the Iranian ethnic group, along with Tajiks, Afghans, Kurds. In the study it was found that in demented Osetians, compared with Russian patients, the level of ideator components of depression, dysphoric disorders, alexithymia, vagotonic symptoms and somatic components is higher.

In another study of this team, a comparative clinical epidemiological analysis of depressions in Russian (Moscow) and Bulgarian (Sofia) populations was conducted. The subject of the study was patients with depressive disorders, identified in obscheomaticheskikh polyclinics. According to the basic clinical parameters (hypotomy, anxiety, exhaustion, affectation of affect, diurnal mood swings, sleep disorders), patients of comparable nationalities practically do not differ. At the same time, Russian patients are more often identified with low-value ideas, anhedonia, weak-willedness, a narrowing of the range of associations, and in patients with Bulgarians - bodily sensations.

Of the recent works on the ethno-cultural aspects of depressive pathology, attention is drawn to the study by O. Khvostova (2002), who studied depressive disorders in Altaians, a small population that is indigenous to the Republic of Altai and belongs to the Turkic ethnic group. Their peculiarity is the presence of sub-ethnoses living in various climatic and geographic conditions: the Telengit subethnos, which are formed by the inhabitants of the "high mountain" (up to 2,500 m above sea level, the extreme climate equivalent to the Far North), and the sub-ethnos of Altai-kizhi. The specificity of the latter is that one part of it lives in conditions of the "middle mountain" (the height is up to 1000 m above sea level), and the other is "low mountains" (intermountain valleys at an altitude of 500 m above sea level with a comparatively favorable climate).

The study found that the prevalence of depressive disorders in Altaians is quite high - 15.6 per 100 surveyed. In women, depressive disorders occur 2.5 times more often than in men. The differences in the morbidity of depressive disorders in representatives of Altai subethnoses are of interest. The maximum level is observed among the residents of the high mountain range (19.4%), then in the middle mountains (15.3%) and the lowest level is registered in the sub-ethnos living in more favorable conditions of low mountains (12.7%). Thus, the prevalence of depressive disorders within the same ethnos depends to a certain extent on climatogeographical conditions and the degree of social comfort of living.

Concluding a brief analysis of the literature on the ethno-cultural peculiarities of depressive disorders, it is not difficult to conclude that, despite the unconditional significance of these aspects, they continue to be insufficiently studied both in the world and in domestic psychiatry.