Development of a measure of the impact of chronic parental illness on adolescent and adult children. The parental illness impact scale (Parkinson's disease).

Although chronic illness is likely to affect the well-being of patients' children, no assessment tools are currently available to measure this impact of parental illness. We therefore developed such an instrument based on interviews with children of patients with Parkinson's disease (PD). This questionnaire and other measures of psychological well-being were completed by 89 children, aged 12-48, years of patients with PD. Factor analysis revealed six domains with 38 questions. These six domains of the 'Parental Illness Impact Scale (Parkinson's disease)' or PIIS (PD) had satisfactory internal consistency and validity. Its six sub-scales correlated significantly and differentially with corresponding measures, including the Quality of Life in Epilepsy Inventory for Adolescents (QOLIE-AD-48; r = -0.2 to 0.85), the Beck Depression Inventory (r = -0.07 to -0.40) or Birleson Depression Self-Rating Scale (r = 0.04 to -0.62), and the Rosenberg Self-Esteem Scale (r = -0.01 to 0.33) as well as age (r = -0.37 to 0.28) and parent's disease duration (r = -0.31 to 0.34). The PIIS is the first instrument to assess the impact of parental illness on children. Its psychometric properties should be tested further in larger samples, including children of patients with other chronic disorders such as multiple sclerosis or chronic heart disease.