Cost-effectiveness of pharmacological and psychosocial interventions for schizophrenia

Information on cost-effectiveness of interventions to treat schizophrenia can assist health policy decision making, particularly given the lack of health resources in developing countries like Thailand. This study aims to determine the optimal treatment package, including drug and non-drug interventions, for schizophrenia in Thailand.

A Markov model was used to evaluate the cost-effectiveness of typical antipsychotics, generic risperidone, olanzapine, clozapine and family interventions. Health outcomes were measured in disability adjusted life years. We evaluated intervention benefit by estimating a change in disease severity, taking into account potential side effects. Intervention costs included outpatient treatment costs, hospitalization costs as well as time and travel costs of patients and families. Uncertainty was evaluated using Monte Carlo simulation. A sensitivity analysis of the expected range cost of generic risperidone was undertaken.

Generic risperidone is more cost-effective than typicals if it can be produced for less than 10 baht per 2 mg tablet. Risperidone was the cheapest treatment with higher drug costs offset by lower hospital costs in comparison to typicals. The most cost-effective combination of treatments was a combination of risperidone (dominant intervention). Adding family intervention has an incremental cost-effectiveness ratio of 1,900 baht/DALY with a 100% probability of a result less than a threshold for very cost-effective interventions of one times GDP or 110,000 baht per DALY. Treating the most severe one third of patients with clozapine instead of risperidone had an incremental cost-effectiveness ratio of 320,000 baht/DALY with just over 50% probability of a result below three times GDP per capita.

There are good economic arguments to recommend generic risperidone as first line treatment in combination with family intervention. As the uncertainty interval indicates the addition of clozapine may be dominated and there are serious side effects, treating severe patients with clozapine is advisable only for patients who do not respond to risperidone and only in the presence of a stricter side effect monitoring system than currently exists.