Introduction: The COVID-19 pandemic affected everybody on Earth. Aside from biological effects on human body, harmful psychosocial events, such as mass quarantine measures, were involved. The situation of pandemic was shown to alter the clinical presentation of psychotic disorders, as well. Purpose of the study: To assess possible changes of clinical presentation in young patients with first-episode psychosis during the COVID-19 pandemic. Materials and methods: The research was conducted at Early psychosis unit of Mental health clinic No.1 named after N.A. Alekseev, Moscow, Russia. In total, 66 patients were enrolled, who met the inclusion criteria: first in life admission to a mental health care unit occurred during the spring of 2019 (comparison group) or spring 2020 (main group), diagnosis on admission belonged to the group “Acute and transient psychotic disorders” (F23.XX). Patients with disability or clinically significant somatic or neurologic condition were excluded from the study. Assessment of patient’s condition upon admission included psychiatric status, distinctive clinical features, psychometric scaling using PANSS. Obtained data were compared between main group and comparison group. Results: We observed an increase in rates of affective and catatonic subtypes of psychoses, with corresponding decrease in rate of delusional subtype. PANSS scores differed significantly for different clinical subtypes of psychoses, albeit differences between main and comparison group showed no statistical significance. In 2020, considerable decrease in total number of hospitalizations was revealed, possibly representing poor accessibility of psychiatric care during the COVID-19 pandemic. Conclusion: Obtained results contribute to understanding the influence of large-scale social calamities, COVID-19 pandemic in particular, on the clinical features of psychotic disorders. Information regarding the effects of named calamities on mental health may help deliver better mental healthcare to patients with first-episode psychoses in the event of global social disasters.