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