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.