Background: dysthymia, also known as Persistent Depressive Disorder (as defined in DSM-5), is a chronic form of depression characterized by less severe but enduring symptoms compared to major depressive disorder., Dysthymia often presents covertly in children and adolescents, masked as personality traits, behavioral peculiarities, or somatic complaints, which complicates timely diagnosis and treatment. The aim of review was to synthesize current evidence on dysthymia in children and adolescents, including its epidemiological profile, diagnostic criteria, clinical presentation, comorbidities, and contemporary treatment approaches. Material and Methods: a literature data search was conducted using databases such as Elibrary.ru, PubMed, Scopus, PsychINFO, MedLine, and Google Scholar, employing keywords including “dysthymia”, “major depressive disorder”, “children and adolescents”, “persistent depressive disorder”, and “comorbidity”. Articles published in Russian and English from 1984 to 2025 were included. A total of 464 sources were screened, 232 selected, and 72 analyzed in detail. Discussion: epidemiological studies show that dysthymia (or persistent depressive disorder) has maintained stable prevalence rates across various age and demographic groups over the past decades. The etiopathogenesis of adolescent dysthymia is complex and multifactorial, involving both biological (including genetic, neurochemical, neuroendocrine, and immunological) and psychogenic factors. Recent research indicates that dysthymia is not merely a subtype of major depression but represents an independent form of affective pathology with a distinct pathogenetic profile. The atypical presentation of depressive symptoms in children and adolescents complicates differential diagnosis between major depression and dysthymia. In both major depression and dysthymia, the following affective disturbances have been identified: low mood, loss of interest in school and daily activities, expressions of aggression and self-aggression, suicidal thoughts, and low academic motivation. Dysthymia is often inadequately treated; many patients do not respond to therapy or continue to experience residual symptoms after treatment. Conclusion: the issue of dysthymia in childhood and adolescence is of particular importance from both clinical and social perspectives. The questions of nosology, classification, diagnosis, and prognosis of chronic depressive disorders in this population remain the subject of ongoing debate. Despite its moderate affective symptomatology, dysthymia is characterized by a prolonged, debilitating course that impacts emotional development, cognitive functioning, school adaptation, and overall personality formation. An important direction for future research is the identification of different developmental pathways of dysthymia and the selection of treatment strategies tailored to specific etiopathogenetic subgroups.