In the medical literature, one can find some differences in the reported incidence rates of depression, a tendency to expand the range of their fluctuations and a progressive increase in the numbers characterizing its prevalence of depression, especially in the second half of the twentieth century. So, in particular, in the early 90s, the prevalence of depression was in the range of 4.4 – 19.9 %. By the end of the 1990s , the prevalence of this disease was already estimated at about 25%, and the lifetime risk of clinically significant depression was 8-9%.                         

In the United States, among the patients of public psychiatric hospitals, the proportion of patients, depression, accounted for 25 %, and among the patients of private psychiatric clinics there were twice as many.         

The results of recent studies confirm a higher incidence of depression and associated suicides, often in combination with drug abuse in people born in the second half of the twentieth century.      

With age, the frequency of depression increases: from 18 to 25 years old , about 5% suffer from it , from 25 to 45 – about 8%. It should be noted that at a later age, depression accounts for up to 50% of all mental disorders.              

The rise in the incidence of depression is partly related to general aging of the population, as, as noted above, the likelihood of depression increases with age .   

At the same time, the dynamics of the incidence of depression is affected by the expansion of ideas about the disorders of the depressive spectrum, especially concerning its “soft” pole and including erased depressions, often accompanying diseases of internal organs. Changes in the structure of depression, an increase in the number of “light”, “erased”, “masked”, undoubtedly leads to the complexity of its recognition and treatment.       

In recent years, there has been an increase in the proportion of protracted and treatment- resistant depression. Such states reach 25% of their total number.      

At the moment the incidence of major depressive episode 1% in men and 3 % in women, the incidence of – 2.5 % in men and 7.5 % in women.        

In recent years, the concept of depression as a condition that occurs mainly in psychiatry has been revised . This problem is becoming one of the central ones in the work of general practitioners.      

Patients with manifestations of depression are quite common among those who seek medical help . These patients often do not realize that they are suffering from depression and turn to general practitioners with complaints that make it difficult to assess their condition correctly .       

Depression is recorded in about 20% of all patients who seek medical help.  

In developed countries (Sweden, Spain, USA, Australia, Japan), the frequency of depression in patients in conventional hospitals is 20-29%   

According to the opinion of Russian scientists in Russia , anxiety or depression was found in 68% of patients applying to the district clinic . The proportion of depression in ordinary hospital patients is about 30%. Among elderly and senile people who go to the polyclinic, patients with depression correspond to 20%         

Specialized mental health care increases the likelihood of detecting depression. When studying the patients of the psychiatric office of one of the territorial polyclinics in Moscow, the proportion of depressive disorders was approximately 38%.   

According to the latest data , there are 2-3 patients with depression for every 30 patients who see a general practitioner .