Quality of life instruments used in mental health research: properties and utilization

Quality of life (QoL) assessment is increasingly used in mental health. Multiple instruments exist, but the conditions for choosing one instrument over another for purposes of a specific study are not clear. We performed a systematic review to identify the QoL instruments used in mental health. The instruments were systematically described regarding their intrinsic properties (e.g., generic v. disease-specific) and their characteristics of utilization in studies (e.g., study objectives). Using cluster analyses, we investigated the existence of similar instruments with respect to each of these sets of characteristics and studied potential links between instruments' intrinsic properties and their characteristics of utilization. We included 149 studies in which 56 distinct instruments were used. Similarities were found among instruments in terms of their intrinsic properties as well as their characteristics of utilization, leading to the construction of four clusters of instruments in each case. However, no relevant links were identified between instruments' intrinsic properties and their characteristics of utilization, suggesting that the choice of QoL instruments did not depend on their properties. A consensus about common QoL instruments must be reached to facilitate the choice of instruments, the comparison of results and thus to have an impact on clinical and policy decision-making.