Purpose: The purpose of this study was to create and validate a mental health subscale for the Quality of Well-Being Self-Administered (QWB-SA).
Methods: The QWB-SA and other measures such as the Profile of Mood States (POMS), Medical Outcomes Study 36 Item Short Form (SF-36), EuroQOL 5D (EQ-5D), and Health Utilities Index Mark 2 (HUI) were administered to three samples: a general population (N = 3,844), a non-psychiatric medical population (N = 535), and a psychiatric population (N = 915). Independent expert ratings of which items represented the construct of mental health were used along with psychometric methods to develop and validate a 10-item QWB-SA mental health scale.
Results: The mental health scale demonstrated high internal consistency (Cronbach's alpha = 0.827-0.842) and strong correlations with other measures of mental health, such as the POMS (r = -0.77), mental health scale from the SF-36 (r = 0.72), EQ-5D mood item (r = 0.61), and HUI Emotion Scale (r = 0.59). It was not highly correlated with measures of physical health. Among the psychiatric population, the new mental health scale was moderately correlated with indicators of psychiatric problem severity.
Conclusions: It is now possible to report outcomes and relationships with mental health in studies that use the QWB-SA. This new mental health subscale can also be used with the large volume of previously collected data using the QWB-SA to examine the impact of illnesses and interventions on mental health-related quality of life.