Schizophrenia is characterized by profound disturbances in cognition,
emotion, and social functioning. Catechol-O-methyl transferase (COMT) is
the important enzyme for the metabolism of monoamines, which play
important part in the pathogenesis of schizophrenia. COMT exists in high
and low activity forms. The low activity form was found to be an amino
acid substitution (Val-108-Met), which reduces the thermostability of the
enzyme. This genetic polymorphism has been reported to be associated with
schizophrenia and its associated clinical features (Li
et al., 1996).