Introduction. The clinic of affective pathology is versatile, it depends on many factors, their interaction (genetic predisposition, nosological predisposition, age, gender, comorbid symptoms), can lead to extreme disability of the patient. It affects more than 300 million people worldwide. According to published data, depression in the elderly (aged 55 to 74 years) is most common (in 39% of cases), cognitive deficits and symptoms of depression often overlap. Based on DSM-5 (The Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition), diagnostic criteria for a major depressive episode include a “decreased ability to concentrate and / or indecision” patients. Aim of the study. The aim of the work is to study the interaction of affective and cognitive functions in patients. Materials and methods. We studied 20 literary sources dedicated to the clinic of mixed conditions (affective and cognitive pathology), as well as psychometric scales: Zung SelfRating Depression Scale, the Beck Depression Inventory, the Criteria for Epidemiologic Studies-Depression scale, and the Yesavage Geriatric Depression Scale which are recommended for patients with pathology of cognition and affect. Results. Cognitive, short-term and long-term functional disorders are one of the most frequent persistent affective symptoms. They can affect motivation and quality of life. Cognitive deficiency may precede a depressive episode, appear simultaneously or follow it. Cognitive  impairment can affect attention, verbal and non-verbal learning, short-term and working memory, may show reduced ability to think, visual and auditory processing of information and its speed, problem solving, motor function, affect professional, family and social activity. Depressed patients think and act slowly, show indecision, inability to make decisions. This is called psychomotor inhibition. Conclusions. It is believed that recurring episodes of depression may increase the tendency to further cognitive deficit, and functional impairment in a patient with depression is caused by cognitive dysfunction. Assessment of cognitive function should be performed in all patients with depression. Laboratory studies may be useful in the diagnosis of comorbid diseases, which can manifest themselves as the dyad “depression and decreased cognitive function”. Neuroimaging methods (computed tomography or MRI of the brain) can help diagnose a neurological disease that can cause psychiatric symptoms (affective and cognitive pathologies).