Adherence patterns with first- versus second-generation antipsychotics for newly diagnosed schizophrenia in Taiwan

The aim of this study was to compare the early adherence patterns for first-generation antipsychotics and second-generation antipsychotics during the first month of treatment for patients newly diagnosed as having schizophrenia.

With a random sample from the Taiwan national health insurance database, persons with a schizophrenia diagnosis (ICD-9-CM code 295.X) and a concurrent initial antipsychotic prescription from 1998 to 2006 were defined as being newly treated for schizophrenia. Adherence patterns within one month of diagnosis were categorized into four independent groups: refill, switch, admission, and discontinuation.

Treatment initiated with first-generation or second-generation antipsychotics resulted in similar rates of refill (57% versus 59%). However, patients who started with first-generation antipsychotics were significantly less likely to switch (9% versus 14%) but more likely to discontinue (34% versus 26%) medications than those whose treatment was initiated with second-generation antipsychotics.

The data substantiated previous observations of the magnitude of adherence problems in Asian populations and highlight the importance of developing new strategies for intervention.