Authors studied the influence of psychosocial group therapy (PST) in adolescents with schizophrenia spectrum disorders on the dynamics of their social functioning based on the PedsQL questionnaire and the CGAS children general functioning assessment scale. There was a statistically significant improvement of basic indicators of adolescent social functioning in the main group after the PST cycle (3 months), while no proven between main and comparison groups difference was detected in the therapeutic dynamics, according to the PANSS scale, that confirmed the effectiveness of PST inclusion into psychosocial therapy and rehabilitation of adolescents with schizophrenia spectrum disorders. Three groups of adolescents were defined within the main group; trends towards changes in social functioning, depending on the type of disease course, were noted.