Abstract Clozapine is the most effective and only approved drug for treatment-resistant schizophrenia (TRS). Studies based on data up to 2014 concluded that it is underutilized in most industrialized countries, including Germany. Since 2019, national guidelines have explicitly been recommending clozapine as first-line therapy in TRS. We aimed to assess whether clozapine use in Germany has increased in recent years and to examine regional variations. Using claims data covering about 20% of the German population (GePaRD), we calculated the yearly prescription prevalence and incidence of clozapine among individuals aged 0–64 years based on outpatient dispensations. For 2022, we also assessed regional variations in clozapine prescription prevalence at the district level (restricted to N = 202 districts with ≥20,000 individuals). From 2012 to 2022, the overall (age- and sex-standardized) prescription prevalence of clozapine continuously decreased by 16% (from 77.6 to 65.5 per 100,000). The relative decline was greatest in women aged 30–39 years (-51%) and in men aged 30–34 years (-57%), in urban areas (large urban cities: -23%; urban districts: -16%), and in regions with high socioeconomic status (-22%). Over the same period, the overall prescription incidence of clozapine decreased by 41%. In 2022, regional clozapine prescription prevalence differed up to 39-fold. In conclusion, clozapine prescribing in Germany did not increase from 2012 to 2022, despite new clozapine-favoring guidelines, and showed substantial regional variation. Our results suggest a persisting underutilization of clozapine in most of Germany. Further research on barriers and facilitators for clozapine use in Germany is needed.
Scholle et al. (Thu,) studied this question.