Paper presents results of validation of the Russian version of The Revised Illness Perception Questionnaire developed by R. Moss­-Morris and colleagues for the diagnostic of patient’s beliefs about causes, duration, consequences, treatment of illness, and their ability to control it. The sample (N=80) included three groups of patients aged 17—26 years (mean age 20.2±2.8 years) with non­psychotic depression within mood disorders (n=33), personality disorders (n=22) and schizotypal disorder (n=25). In order to establish the external validity of the questionnaire patients filled Beck’s Cognitive Insight Scale, Illness­ and Treatment­Related Locus of Control Scale and Treatment­Related Self­efficacy Scale . Factor validity and reliability of IPQ­R was demonstrated . Patients of all three groups tend to explain their illness by personality and (to a lesser extent) situational factors, to believe in the importance and effectiveness of the treatment, in their ability to control their illness. They consider illness as short­term and not of a cyclical nature. Supporting the external validity of the questionnaire we demonstrated that beliefs about illness and its reasons correlates with results of the interview, cognitive insight, illness­ and treatment­related locus of control and treatment­related self-efficacy.