Background. The trend of recent years is a steady increase in mental illness among the population. according to the statistics of the ministry of health of the russian federation, mental disorders were classified as socially significant diseases in russia in 2018. Thus, the absolute number of patients with a first-time diagnosis of a mental disorder who applied for counseling and treatment in the Russian Federation in 2018 was 379818, which is 3.4% more than in 2017. [20,21,22,23,24] the number of patients with a first-time diagnosis of " mental disorder (except for diseases related to the use of psychoactive substances)" taken under dispensary observation in the republic of mordovia in the same year was 35.5 per 100,000 population. In addition, mental illnesses are in third place among disabling diseases, second only to malignant neoplasms and diseases of the circulatory system. In the structure of repeated disability by class of diseases, this group of diseases is 9%, and the lion's share falls on people of working age. Thus, there is a steady increase in mental illnesses, as well as disability due to them [1], [3]. The question arises of the need to study the patterns of disability formation in order to further develop theories and concepts of ways to protect human health, prevent disability, assess the rehabilitation potential and prognosis, develop rehabilitation measures that improve social adaptation and integration of patients in the family and society. The aim- study of the patterns of disability formation due to organic mental disorders in the Republic of Mordovia, taking into account age characteristics and severity of disability, which is important for the development of comprehensive measures for the prevention of morbidity, early diagnosis and rehabilitation of this group of people. Materials and methods. The analysis included information from the statistical collections of Rosstat and approved forms of state statistics No. 7-sobes for 2019. The data of all first-time persons recognized as disabled due to mental disorders in the Republic of Mordovia for 2014-2019 on the basis of the ITU information base for the Republic of Mordovia are analyzed using a continuous method. Results. Having analyzed the data of all first-time persons recognized as disabled due to mental disorders in the Republic of Mordovia for 2014-2019 on the basis of the ITU information base for the Republic of Mordovia, it was concluded that a significant place in the structure of disability is occupied by organic mental disorders. The percentage of people with organic mental disorders among those first recognized as disabled 18 years and older over the past five years is significant and stable, ranging from 20.1 (in 2017) to 25.1 (in 2014). In the structure of patients who were diagnosed with disability with this diagnosis, there is a predominance of repeated patients over primary ones (by 23.6 %), and it should be noted that this pathology is more common in men (71% of the total number of persons (or in the population) with the above diagnosis). Patients with both primary and re-recognized disabilities with a diagnosis of "Organic mental disorder" were more often assigned to the third group of disability (62% of cases among primary, 57.4% among repeated). Also, the third group of disability prevails regardless of the patient's gender. The study of age-related features of disability due to organic mental disorders in the Republic of Mordovia in 2019 showed that organic mental disorders are most often found in the working-age population. In addition, the proportion of young people (from 18 years to 44 years) is high, it is 59.2% for men, 50% for women. Conclusions. Given the steady increase in mental illness and disability as a result of it, it is necessary to study the theories and concepts of medical and social expertise and rehabilitation of patients suffering from mental disorders. The role of fundamental and applied research in the field of medical and social expertise and medical and social rehabilitation is significant in order to create ways to protect human health, prevent disability, and develop factors that improve social adaptation and integration of patients in the family and society. in order to develop such concepts, it is necessary to study the structure of disability, the patterns of formation, and the peculiarities of the influence of age and gender factors.