Quality-of-life assessment in schizophrenia: the unfulfilled promise

Keywords::

• clinical care
• clinical trials
• cost–utility
• quality of life
• quality-of-life assessment
• schizophrenia

Although the origins of the modern construct of ‘quality of life’ are not known, the improved standards of living that accompanied post-war economic prosperity have created the expectations in many western societies of psychological fulfillment, satisfaction and wellbeing. Social scientists were quick to seize on such a construct, and advanced population-based quality-of-life research that generated extensive ‘social indicators’ data. The first mention of the term ‘quality of life’ in the public arena was by US President Johnson in his 1964 landmark address on ‘the great society,’ influenced by the writings of the well-known economist of that time, John Kenneth Galbraith, about the ‘affluent society’. Since then, the concept of quality of life quickly gained currency as it also got picked up by the popular press [1].

In 1947, the WHO broadened the definition of health as ‘a state of complete physical, mental and social wellbeing and not merely the absence of disease and infirmity’. Over the next few decades, quality of life has become a new paradigm representing the new image of modern medicine. To narrow the broad concept of quality of life in general, the term ‘health-related quality of life’ was introduced to define its boundaries and focus research approaches on health-related issues [1].

Quality of life in schizophrenia

Historically, interest in quality of life in schizophrenia started as an extension of the increasing concern about the state of the chronically mentally ill in the community following the precipitous deinstitutionalization that took place in the early 1960s [2]. Issues such as personal safety, social isolation and poverty came to be recognized as the personal concerns of patients discharged from mental hospitals to a community that was not prepared to receive them [3]. With the rise in interest in the concept of health-related quality of life, a number of scales were developed and a number of researchers embraced and advanced the concept of quality of life in their publications (including Bachrach [3], Lehman [2], Awad [4] and others). However, the development of the concept of health-related quality of life as applied to schizophrenia seems to have been rather slow compared with its development in other medical areas [5]. The factors that seem to have impeded the development of quality-of-life research in schizophrenia include: lack of agreement on a definition; lack of theoretical and conceptual models and multiplicity of measuring instruments that frequently lack any conceptual foundation and only reflect the theoretical orientation of the instrument developer – a situation that has led to the absence of any common metrics to allow for a meaningful comparison of data or inform about what the data mean. As schizophrenia impacts on a number of significant mental and psychological aspects of patient functioning, including affect, thinking, cognition and behavior, the reliability of self-reports by patients about their assessment of quality of life was frequently doubted, even though a number of researchers confirmed the reliability of the majority of persons with stable schizophrenia in assessing their level of satisfaction, inner feelings and quality of life [6]. Some researchers took to defining quality of life relying on objective domains such as housing or finances, which are mostly a reflection of quality of living rather than adhering to the original concept of quality of life as a subjective construct [7].

Current status of quality-of-life assessments in schizophrenia

Over the past few decades, there has been extensive growth in the number of quality-of-life publications in schizophrenia, yet there have also been increasing concerns about the usefulness of the concept of quality of life as a result of its lack of impact on clinical care. Similarly, the initial promise for the development of new methodologies for health economics and particularly pharmacoeconomics based on quality-of-life data did not fully materialize. Such concerns have not only shrouded the concept of quality of life in some doubt but have also raised questions about the soundness of its theoretical and conceptual scientific foundation.

Lack of impact on clinical care & clinical trials of antipsychotics

In reviewing the large number of quality of life-related studies in schizophrenia over the past 25 years, unfortunately the majority of such studies have mostly reported data related to quality-of-life measurements [7]. Not many studies have gone beyond measurement in order to take quality-of-life studies to its next ultimate step: integration of quality-of-life data into healthcare plans. Very few studies have explored aspects of the conceptual and theoretical foundation of the construct itself in order to enhance our understanding and better development of theory-based measuring tools [7]. In addition, little is known about whether any improvement in quality of life in persons with schizophrenia can contribute or lead to other desirable outcomes, such as better compliance behavior or less utilization of health and psychiatric resources [8,9]. Overall, a somewhat pervasive feeling has developed among clinicians that spending resources on measurement of quality of life is more of a distraction since not much is known about what to do with such data. Similarly, there has been reluctance in including quality-of-life assessments in clinical trial protocols for new antipsychotic medications. The multiplicity of measurement scales, the lack of standardized common metrics and the lack of sensitivity to pick up small changes as expected in such relatively short-term clinical trials have all in some way contributed to a lack of interest in quality-of-life measurements in clinical trials of new antipsychotics [10,11].

Lack of impact on health economics & pharmacoeconomics

It is well recognized that schizophrenia is probably one of the most costly psychiatric illnesses, not only in terms of direct cost but also as a result of its long-term impact, requiring intensive medical psychiatric care as well as the indefinite need for social economic support and loss of productivity [11]. At a time of economic constraints, it is paramount to demonstrate the cost–effectiveness of psychiatric interventions for the purpose of allocation of resources and policy decision-making. One of the promising approaches in cost–effectiveness analysis has been the cost–utility approach based on the preference for a certain health state. In essence, utility measurement can serve as an alternative means for appraising the quality of life of individuals affected by schizophrenia. Although we and others have demonstrated the feasibility of cost–utility approaches in schizophrenia, very few researchers have pursued such an approach, as judged by the very limited number of publications [12–14]. A number of factors may have limited the popularity of such an approach. Although the cost–utility approach is methodologically appropriate and based on sound economic theories, the design is frequently complex and requires some degree of cognitive intactness of patients, which limits its use among the broad spectrum of patients with schizophrenia. There is also ongoing concern about whether utility approaches can reflect individual preferences since the calculation of years of life adjusted by weights (quality-adjusted life-years) can only partially incorporate patients’ preferences as the utility approach is only used to obtain the weights. Another concern is how to establish the reliability and validity of the weights assigned [13]. It is also not clear whether the utility approach can allow for the examination of the effect of various interventions on quality of life as it does not provide a profile of quality of life but instead establishes a numerical score to be used for comparison [13,14]. Such a numerical score is unlikely to be of great use in individual clinical decision-making because clinicians need to identify the deficit in order to take corrective action. One of the central questions is how to value health in calculations of quality-adjusted life-years and which appropriate methods can be used to obtain utilities – questions that remain largely unresolved [15]. The subjective nature of quality of life, as well as the symptoms of schizophrenia, may introduce a bias, as a person suffering from schizophrenia can assign higher utility to decreased health states compared with healthy individuals. On the other hand, it is desired that patients rather than clinicians or experts assign utility, which is consistent with the true sense of the term preference-based evaluation. This raises doubts about the limited value of surrogate rating from proxies. Many of these concerns have rarely been seriously pursued as no adequate conceptual model has been developed to enhance our understanding. One of the challenges we observed is how to bring clinicians and health economists, each one speaking a different language, to work together. Clinicians need to grasp the complexity of health economic theories and health economists need to be fully aware of the intricacy of various clinical and human dimensions.

Concluding remarks & the way forward

I strongly believe that the construct of quality of life in schizophrenia is important and useful as it embodies all that the patients, their families, the doctors, policy-makers and society at large aspire to achieve. However, for such worthwhile goals, the field of quality of life in schizophrenia needs to reinvent itself in order to enhance its scientific foundation, and develop sound methodological as well as effective strategies for integration of quality-of-life data into healthcare plans. There needs to be close collaboration between practicing clinicians and health economists in order for both to be able to translate utility analysis data into meaningful information for clinical decision-making. Failing to demonstrate a positive impact of quality-of-life assessments on clinical care or on cost–effectiveness analysis and policy decision-making can ultimately lead to a decline of interest and the important and valuable concept of quality of life to fade away.

Financial & competing interests disclosure

The author has no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties.

No writing assistance was utilized in the production of this manuscript.