Disability was assessed with the physical component summary, mental component summary, social functioning scale, role emotional scale, and mental health scales of the Short-Form-12v2 (SF-12), a reliable and valid measure in population surveys (Ware et al., 2002). The SF-12 is used across a wide range of clinical and research settings to provide self-reports of behavioral functioning and perceived psychological well-being independent of age, disease, or specific treatment. Each SF-12 norm-based disability score is a continuous variable with a mean of 50 in the general population, standard deviation of 10, and range of 0–100. Lower scores indicate greater disability and have been associated with psychopathology in prior studies (Compton et al., 2007).
