Patterns and costs of antipsychotic drug use in Taiwan: 1997 to 2001

The advent of atypical antipsychotics greatly changed the treatment pattern for mental illnesses worldwide. This study was designed to determine the trend in prevalence, prescribing pattern, and cost of antipsychotic agents in Taiwan from 1997 to 2001. Data were obtained from claims completed for a random sample of 200,000 people registered with the National Health Insurance program. The antipsychotics monitored included all group N05A drugs in the Anatomical Therapeutic Chemical classification system (version 2000). Conventional and atypical antipsychotics were handled separately. Of the 195,971 eligible registrants, 37,441 (19.1%) received any kind of antipsychotic during this 5-year period, but only 713 (0.4%) used atypical antipsychotics. The prevalence of conventional antipsychotic use during each successive year of this study was 5.2%, 5.7%, 6.6%, 6.2%, and 6.1% and 0.1%, 0.1%, 0.1%, 0.2%, and 0.3% for atypical agents. Although far fewer registrants used them, atypicals comprised 19.1% of all prescribed amounts measured in defined daily doses and 56.1% of the cost for all antipsychotics in 2001. During the 5-year study period, atypical antipsychotics were prescribed for 405 (57%) patients with schizophrenia, 132 (19%) with affective disorder, 128 (18%) with other psychiatric disorders, and 48 (7%) with a nonpsychiatric disorder. With the loosening of reimbursement restrictions in 2002, continued growth of atypical antipsychotic use in Taiwan might be expected.