Introduction

Prescribing of psychotropic drugs, such as antipsychotics, antidepressants, anxio- lytics and mood stabilizers, is common in psychiatric inpatients for acute and maintenance treatment of psychiatric illness.

While no one will disagree that the psychotropic drugs should be kept to an effective minimum dosage, it is reported that Asian patients usually require a lower dosage of antipsychotic drugs than Caucasian patients (Chiu et al., 1992; Ko et al., 1989). The differences in prescribing patterns are not just observed in the dosages of psychotropic drugs, but are also seen in the types of psychotropic drugs, the use of poly-antipsychotic drugs, and the concurrent use of psychotropic drugs. Generally, prescribing patterns may be based on the following factors:

1. biological factors including genetic susceptibility to adverse effects (Lam et al., 1995). Some researchers have argued that ethnicity may provide a marker for individual genetic variation, and that drug choice and dose should vary according to different races (Jones & Perlis, 2006);

2. ethnicity factors (Opolka et al., 2004), in that Caucasian patients were more likely to receive an atypical antipsychotic and less likely to receive a depot injection than Latino patients (Covell et al., 2002);

3. prescribers' professional training, where postgraduate and continuing medical education can affect the prescribing habit (Hull et al., 2005). Findings from clinical trials, particularly results from industrial sponsored clinical trials may influence prescribing patterns (Perlis et al., 2005);

4. health care system and medical insurance (Sleath & Shih, 2003).

In 1999, the first collaborative attempt to study the prescribing of psychotropic drugs in several East Asian countries was initiated.