The aim was to study immediate and long-term (post-therapeutic) effects of a three-month course of therapy with citicoline in 1st-degree relatives of patients with Alzheimer’s disease (AD). All the included relatives of patients with AD revealed signs of minimal cognitive dysfunction (MCD) and mild cognitive decline syndrome (MCI — Mild Cognitive Impairment, ICD-10 code F06.7). Study participants: the study involved 90 first-degree relatives: 24 with MCI and 66 with MCD. Study design: an open-label comparative multidisciplinary study of the six-month dynamics of cognitive functioning of two groups of relatives who received a three-month course of citicoline therapy. The baseline indicators of the cognitive functioning of relatives with MCI syndrome and MKD were compared with the indicators at the end of the three-month course of therapy with citicoline at a daily dose of 1000 mg as well as 3 months after the end of the course of treatment. Methods: clinical, psychopathological, neuropsychological, psychometric, genetic, statistical ones. Results: а significant positive effect of the course therapy with citicoline on the cognitive impairment of 1st degree AD-patients’ relatives with minimal cognitive dysfunction and more pronounced cognitive impairments met the diagnostic criteria for MCI syndrome has been found. A significantly greater value of both immediate and long-term therapeutic effect of MKD compared with MCI in relatives was established by psychometric and neuropsychological indicators characterizing voluntary memorization of verbal and visual stimuli, optical and spatial activity, voluntary attention, and associative verbal thinking. Conclusion: the results of the study can be used as the basis for a model of prevention of the progression of cognitive deficit and the development of dementia in persons with a high risk of developing AD, i.e. in individuals with both genetic risk and signs of cognitive impairment.