IntroductionCognitive perspective considers beliefs as key factors of compliance and adjustment in mental disorders (Beck, 2011) that are especially important in youth. In psychosis illness, representation is related to CBT efficacy.ObjectivesWe suggest that in different mental disorders different illness-related beliefs are important for quality of life domains.AimTo reveal relationships between illness representation and quality of life in mental disorders controlling for psychopathological symptoms.MethodsOne hundred and eighteen male patients 17 – 27 years old : 33 with mood disorders, 26 with personality disorders, 27 with schizotypal disorder and 32 with schizophrenia recovering after first episode of psychosis filled Illness Perception Questionnaire, Symptom Checklist 90-R, Quality of Life and Enjoyment Questionnaire (version for mental illnesses).ResultsAfter statistical control for psychopathological symptoms, in personality disorders feeling of personal and treatment control (β = .43–.52, P < .01) as well as belief in longer (β = .42, P < .05) but not cyclic (β = –.65, P < .05) illness duration predicted satisfaction with health while belief in longer duration and less consequences correlated with better satisfaction with leisure time (β = .87, P < .01). In mood disorders, feeling of treatment control (β = .32, P < .05) and belief in shorter illness duration (β = –.37, P < .05) were related to better satisfaction in emotional sphere.ConclusionsBeliefs about illness duration, consequences and control could be important in assessment and CBT for youth with personality disorders while treatment control and illness duration are important in work with youth with mood disorders.Disclosure of interestThe authors have not supplied their declaration of competing interest.