The dissertation is devoted to the complex study of socio-demographic, clinical-psychological, pathopsychological, individual-pathopersonal and psychopathological aspects of depressive disorders taking into consideration gender, age, socio-demographic and clinical pathomorphosis; scientific substantiation and development of a complex system of appropriate medical and psychological support. The dissertation presents theoretical justification and a new solution to the current scientific problem of medical psychology to improve the system of medical and psychological support for patients with depressive disorders, based on study of complex of socio-demographic, clinical-psychological, pathopsychological, individual-pathopersonal and psychopathological factors in context of pathomorphosis. The study was based on a study of the medical records of 403 patients with depressive disorders, who sought medical care in the period 1971-2016, an in-depth study of the medical records of 236 patients with depressive disorders, who sought medical care in the period 1971-1995, and a survey of 245 patients with depressive disorders. It was established that the main trends in age pathomorphosis of depressive disorders are – significantly earlier age of onset and an increase in the age range of the onset of depressive disorders; in gender pathomorphosis – an increase in proportion of women among patients; and socio-demographic pathomorphosis is determined by social trends. It was found that clinical pathomorphosis of initial stage of depressive disorders is characterized by general tendency to an increase of severity of initial symptoms with emotional hyperesthesia, asthenia, somato-vegetative disorders and dyssomnia; manifest stage – a decrease in asthenic symptoms and an increase in anxiety, somato-vegetative and dyssomnic symptoms. In the dynamics of clinical pathomorphosis of depressive disorders, prevalence of anhedonia and low self-esteem decreased, and prevalence of asthenic, cognitive, anxiety, somato-vegetative and dyssomnic symptoms increased. In the intrasyndromological structure, frequency of vital and anesthetic forms decreased with increasing prevalence of apathetic, anxiety-phobic and hypochondriac depression with dyssomnic, somato-vegetative, senesto-algic, asthenic and pathocharacterological syndromes. Clinical pathomorphosis of depressive disorders was more pronounced in the age group up to 30 years. Deterioration of main depressive symptoms with age, was more pronounced in men, with a predominance of anergic and asthenic components, anxiety-phobic and senesto-hypochondriac manifestations in the syndromic structure in women, and of adynamic and dysphoric syndromes in men. Polymorphism of psychopathological manifestations of modern depressive disorders has been revealed, which include, in addition to core depressive and anxiety symptoms, moderate manifestations of interpersonal sensitivity, obsessive-compulsive symptoms and somatization; which increases with age. Persistent pathocharacterological and pathopersonological traits associated with depressive disorders, including persistent dysthymia, anxiety, hypochondriac fixations, affective lability, and psychopathization, have been identified and their gender and age characteristics were defined. It has been established that depressive disorders are accompanied by a significant decrease in vitality and quality of life and social support of patients and severe socio-psychological maladaptation, which worsens with age. It was determined that the main predictors of depressive disorder at the initial stage are low mood, dyssomnia, anxiety, fear, asthenia and somato-vegetative symptoms, and specific gender differences were identified. A mathematical prognostic model for the development of psychosocial maladaptation in depressive disorders has been developed and operational criteria for qualitative and quantitative assessment of the risk of psychosocial maladaptation have been proposed. Taking into consideration the main trends in pathomorphosis of depression and socio-demographic, clinical-psychological, pathopsychological, individual-pathopersonal and psychopathological features of modern depressive disorders, a comprehensive system of medical and psychological support of patients with depression has been developed and implemented. According to the results of approbation of the proposed system, its high efficiency was confirmed.