Utilisation of antipsychotic drug clozapine in Finland is the second highest in the world

The study also demonstrated that the use of clozapine varied considerably between countries. 

“Prior studies have shown that clozapine is consistently under-prescribed, and this is an international problem", says Leena Saastamoinen, Research Manager, Docent at the Finnish Medicines Agency Fimea.

“It is good that the use of clozapine in Finland is one of the highest in the world.” 

In many countries, the levels of utilisation were relatively low in proportion to the actual prevalence of treatment-resistant schizophrenia. In other words, clozapine is generally used less than would be needed. Of the 75 countries examined, only in Finland and New Zealand, the prescription levels of clozapine corresponded approximately to the share of the population with treatment-resistant schizophrenia. 

“Although the use of clozapine had increased in nearly two thirds of the countries examined, the increase was so modest that it does not have a clinically significant effect", Saastamoinen says.

The strictness of blood test monitoring is not linked to the level of clozapine use

The reasons for the insufficient use of clozapine are unclear. The study tested whether different variables could explain the differences between countries in the prescribing levels of clozapine. 

In most countries, including Finland, the prescription and use of clozapine involves mandatory blood test monitoring in order to reduce the risk of adverse effects. Blood test monitoring is required in different ways in different countries. There are differences between countries in how often and for how long mandatory blood test monitoring is required. However, the study found that the strictness of blood test monitoring was not linked to the level of clozapine use.

According to a study carried out by the European Medicines Agency (EMA), blood test monitoring requirements for clozapine treatment are being reduced throughout the EU, as it has been found that neutropenia, a serious adverse effect of clozapine, is at most frequent in the first 18 weeks of treatment. In Finland, blood test monitoring has also been reduced at the end of 2025. However, the study suggests that in order to increase the prescription levels of clozapine, other measures besides streamlining the mandatory blood test monitoring are needed. For example, according to the study, the number of psychiatrists in the country was linked to a slight increase in the level of clozapine use.

In Finland, clozapine is used for severe mental health problems

Treatment-resistant schizophrenia, in which the most commonly used antipsychotic drugs do not have an adequate response, impacts 30–40% of those diagnosed with schizophrenia. The antipsychotic drug clozapine is the only medicine approved for the treatment of treatment-resistant schizophrenia, and international recommendations on psychiatric treatment consider clozapine to be the most effective treatment option. In Finland, clozapine is used almost exclusively under special reimbursement, that is, for the treatment of severe mental health problems, such as schizophrenia. 

The study examined the level and development of clozapine use in 75 countries in 2014–2024. The analysis is the most extensive and up-to-date assessment of international trends in the use of clozapine. The use of clozapine was assessed for the first time in many countries, and extensive comparative data was obtained. 

Read more

Research report on thelancet.com service: Fitzgerald I, O’Dwyer S, Dhubhlaing C et al. Global trends in clozapine utilisation between 2014 and 2024: a longitudinal epidemiological study with data from 75 countries. The Lancet Regional Health – Europe, 2026; 63 

Fimea online news 18 December 2025: Mandatory blood test monitoring required in clozapine treatment is reduced (in Finnish)

For more information, please contact

Leena Saastamoinen, Chief Researcher, tel. +358 29 522 3659 
The email address format is firstname.lastname@fimea.fi