ABSTRACT
Antipsychotic drugs constitute the mainstay of treatment for schizophrenia; they are used
to treat acute psychotic episodes and reduce risk of relapse (1). However, a significant pro-
portion of treated patients (25-50%) fail to show satisfactory recovery, and 80% will have
a relapse within five years (2,3). In addition, between 50% and 70% of the patients develop
severe and lasting side effects as a result of long-term antipsychotic treatment (4). Failure
to find an appropriate treatment is associated with poor prognosis and may reduce chances
of recovery. Early and effective treatment is therefore important. There are two major
classes of antipsychotics, classical and atypical drugs, with different pharmacological pro-
files and varied success in the treatment of the disease. However, at present it is not poss-
ible to determine, other than by a trial of treatment, which individuals will respond to
which drugs. Pharmacogenetic and pharmacogenomic research approaches aim to identify
genetic factors that influence response variability and to use that information for treatment
prediction and selection. Pharmacogenetic research has produced in recent years interest-
ing results that have been translated into useful clinical applications (i.e., determination of
metabolic status). Pharmacogenomic research is producing a wealth of information on
response-related factors, although the clinical utility of this approach will only become
apparent over the next decade.
