Quality of life is often measured using questions about happiness. This method presumes that respondents are able to judge their life. Research suggest that this is typically
the case, but this is not to say that everybody can. In that context one may doubt whether people with a mental disorder can judge their life adequately. Happiness can be rejected as
a indicator for quality of life for people with mental disorders, because of affective and cognitive distortions. We therefore checked the validity of happiness and satisfaction
measures in the context of mental disorders. Psychiatric diagnoses were determined at baseline and at 12 and 36 months follow-up in a representative sample (N = 7,076) of the
Dutch population, using a full Composite International Diagnostic Interview. Respondents indicated how often they had felt happy during the past month and how satisfied they were
with their lives in general. The measurements have a satisfactory concurrent, ecological and predictive validity for people with mental disorders. Though the level of happiness is lower among the people with mental disorders, conditions for happiness and contentment appear to be similar.