Feed

The onset of an illness has the potential to induce profound changes in a person's life. However, being diagnosed with a physical illness may not carry the same impact as being diagnosed with a mental health disorder. Among them, psychotic disorders exhibit the highest level of social stigma and acceptance challenges, along with compromised social functioning, diminished quality of life, and disruptions in personal, social, and vocational domains. The Impact of Illness Scale (IIS) measures how an illness has adversely affected a person's life as perceived by that person. This study aimed to assess the psychometric properties of the IIS in a sample of 141 people with a first episode of psychosis (FEP) (mean age 35.7 years, 51.8% female). The study explored the factor structure, internal consistency, convergent and discriminant validity, and temporal stability of the IIS. The confirmatory factor analysis (CFA) model showed an excellent fit of the data, confirming a one-factor structure, internal solid consistency (McDonald's ω = .95; Cronbach's α = .94), theoretically coherent convergent and discriminant validity with measures of internalized stigma, negative beliefs, symptoms of psychosis and general psychopathology symptoms, and moderate test-retest reliability. Overall, these findings support the IIS as a reliable and valid tool for assessing the subjective impact of psychosis, offering clinical and research utility for understanding patient experiences beyond symptom severity.