Schizophrenia, which is a psychiatric disease, is associated with significant and long-lasting health, social and financial burden, not only for patients but also for families, other caregivers and the wider society. Although the lifetime prevalence has not increased (estimated at 0.5% in a recent systematic review 1), schizophrenia remains among the most burdensome and costly illnesses worldwide. Considerable progress has been made during the last 10 years in the treatment of schizophrenia. Patients with schizophrenia, given the severity of the disorder, usually require long-term health care. Though the economic costs vary from country to country, all the cost-of-illness estimates highlight the heavy societal burden of schizophrenia 2.

In a cross-sectional study, Rouillon et al. 3 estimated the direct and indirect annual (in 1992) cost of medical management of schizophrenia in France to be Fr 12.4 billion ($US 2.34 billion) and Fr 5.2 billion ($US 0.97 billion), respectively.

The main objective of this study was to describe and update the cost of schizophrenia using a longitudinal, representative sample of French schizophrenic patients. The second objective was to identify cost drivers in schizophrenia treatment.

Overall, 288 patients aged 18-64 years were recruited for the study. Sample attrition resulted in 223 participants taking part in the second interview, 196 in the third, 173 in the fourth, and 138 in the final interview.

The cost of schizophrenia has been estimated in a number of studies. The main common result in all of these studies is the elevated hospitalisation cost, which heavily impacts direct medical mental health costs 2.

The main objective of this study was to describe and update resource allocation for French schizophrenic patients, based on the EuroSC cohort, which is a longitudinal, representative sample of French schizophrenic patients. Given the course of the disease, schizophrenic patients’ care is usually managed by their “psychiatric sectors”, French mental health catchment areas. The patient selection process allowed us to obtain a random sample of this population. Moreover, this sample was followed prospectively during a two-year period. Thus, the resource utilisation collection was standardised and prospective.

In France, in 1992, Rouillon et al. 3 were the first to evaluate the cost of treatment in medical and social terms. Because of the different methodology used, a direct comparison with this study is not possible. In the previous study, a mail survey was conducted among all practising psychiatrists in France, who were requested to provide information on the patients they had most recently seen or examined. Unfortunately, the response rate (8%) was very low, raising questions about the representativeness of the sample. By contrast, in the present study, patients were randomly drawn from three defined catchment areas located in Northern, Central and Southern France. While in the previous study the diagnosis was made by the treating psychiatrists, in the present study, it was based on a structured interview (SCID) conducted by trained interviewers. In the previous study, retrospective data on resource consumption were obtained from case files, while in the present study, patients were interviewed 5 times at 6 month intervals. In the previous study, the cost of lost employment was assessed using social assistance allowances, while in the present study, information on employment status provided by patients served as the basis for this assessment. In contrast to the previous study, costs for psychologists, GPs and non-psychiatric specialists have also been included, while costs for intermediate services other than day clinics have not been included.

As usual, the financial costs of schizophrenia to society can be divided into direct and indirect costs. In the study by Rouillon, direct costs included treatment provided in inpatient services (55%), intermediate facilities (30%), outpatient visits (9.5%) and medication costs (5.5%).

In the present study, the breakdown of direct costs was different. The proportions of costs related to inpatient care, day clinic or outpatient care were lower (39.3%, 37.6% and 6.8%, respectively) compared to the Rouillon study, and medication costs accounted for a larger part of the total costs (16.1%).

Even though the present inpatient admission cost is slightly lower than that in the Rouillon study (from 85% to 77.0%), it remained the single largest contributor to French direct costs of treating schizophrenia. The decrease in inpatient admission costs may be attributed to the cost being reported as day clinic hospitalisation.

The contribution of drug costs to the total cost of treatment seems to have increased in France (from 5.5% to 16.1%). In the study by Knapp et al. 2, the use of atypicals had pushed up drugs’ cost contribution to the total cost, partly because of their higher prices and partly because of potential reduction in inpatient stays, thus potentially reducing the total cost.

In another study by Salize et al. (2009) 25, as part of a randomised controlled trial (RCT) in six European sites, the direct mental health care cost for 422 patients with schizophrenia was analysed according to how total and medication costs differed across sites and which variables were likely to predict total or service-specific costs. A difference in the basic study design does not allow direct comparison. In the RCT, although samples were homogeneous, large inter-site cost differences were found (annual means ranging from € 2 958 in Spain up to € 36 978 in Switzerland). In this study, the annual cost was extrapolated to be € 3 796 million. In the RCT, psychopharmacologic costs were much more constant across sites than costs for other services. Total costs were associated more with regional or socio-demographic characteristics than with disorder-related parameters. By contrast, in the present study, costs were virtually unrelated to socio-demographic characteristics. The RCT confirmed remarkable differences in direct costs of patients with schizophrenia across Europe. However, the relative stability of medication costs suggested a need to analyse mechanisms that influenced service-specific costs for schizophrenia. By contrast, in the present study, we found the increase in medication costs in France to be higher and in the range of 5.5% to 16.1%. We also identified several mechanisms, such as depression at baseline, satisfaction with living conditions, social relations, cost of psychiatrists, and financial condition, that affecting the cost of treatment.

In the present study, the indirect cost linked to productivity loss for unemployed patients of working age was estimated as a heavy cost, even if the estimation was only reasonably accurate.

Several cost drivers were identified: positive or depressive symptoms of schizophrenia as well as relapse of symptoms during the follow-up period predicted higher costs; satisfaction with health or negative symptoms of schizophrenia at baseline was linked with lower costs. Socio-demographic characteristics, social and occupational functioning at baseline and number of previous hospitalisations were unrelated to costs. This finding is consistent with the results from the study by Knapp 2.

Our study has several limitations.

First, this study focuses on treatment and health care costs. Although cost of lost productivity through unemployment is included in the analysis, all other indirect costs are ignored. Costs to patients may also include personal suffering, costs associated with premature mortality (whilst premature mortality may be attributable in part to the risks of suicide, it may also be the result of other factors, such as poor living conditions, poor nutrition, or decreased access to healthcare services), costs of informal caregivers (the costs incurred by the family members of the patient incorporate several components, including personal suffering and sometimes loss of productivity that should be assessed as well), criminal justice system costs, social welfare costs, and private alternative therapy costs and may also include intangible costs.

Second, there was a high rate of attrition in the sample. Although this was handled in our statistical analysis, sensitivity analysis using several imputation techniques could provide a better understanding of the variability of the estimates.

Third, comorbidities were not taken into account in this analysis. There is evidence associating other conditions with schizophrenia that also require treatment. For example, people with schizophrenia are more likely to suffer from diabetes and cardiovascular disorders. Economic costs incurred by managing these comorbidities are and will continue to represent a considerable burden on health services 26.

Finally, although large efforts have been made to obtain a representative sample of the French schizophrenic population, we recognise that our results should be taken with caution because of the sample size.

Further research is needed on how to evaluate indirect costs and caregiver costs. Sample attrition in schizophrenia cohorts is common and appropriate techniques should be explored. Finally, comorbid illness (in general and mental health) should be included in further research.

This study described resource allocation in a longitudinal, representative sample of French schizophrenic patients. Cost drivers were also identified.

In the sample of 288 French schizophrenic patients aged 18-64 years, the direct resource allocation showed that inpatient admissions remained the single largest contributor to French direct costs of treating schizophrenia, with day clinic hospitalisation and an increase in the cost of medications included as a part of inpatient admissions. Unemployment was identified as a major indirect cost of schizophrenia treatment.

Positive and depressive schizophrenia symptoms predicted a higher cost of treatment. Health satisfaction or negative symptoms of schizophrenia were linked with lower costs.

We found that schizophrenia is an economic burden in France. Based on the results obtained in France, we suggest further analysis of mechanisms that influence the service-specific costs for schizophrenia in other areas of the world.

The study was funded by H. Lundbeck A/S. The authors declare that they have no competing interests.

ES, DH participated in the design of the study and performed the statistical analysis. ES, DH, JMA, HHK, MCA and MT conceived of the study and participated in its design and coordination and helped to draft the manuscript. All authors read and approved the final manuscript.