Pilot study of the cytochrome P450-2D6 genotype in a psychiatric state hospital.

OBJECTIVE

The authors conducted a pilot study to develop preliminary data on the frequency of cytochrome P450-2D6 (CYP2D6) genotypes in state psychiatric hospital patients and to establish population sizes needed to determine potential clinical relevance in therapeutic outcome.

METHOD

One hundred consecutive inpatients at Eastern State Hospital in Kentucky who provided informed consent were genotyped at the CYP2D6 locus during their hospital stay.

RESULTS

Twelve of the patients were CYP2D6 deficient, and four carried the *1Xn or *2Xn allele associated with ultrarapid metabolism; all of these patients were Caucasian (N=87). The rate of deficiency in CYP2D6 expression in these Caucasian state psychiatric hospital patients (14%) was twice that of the U.S. population (7%). The patients with CYP2D6 deficiency also appeared more likely to experience side effects in response to CYP2D6 medications.

CONCLUSIONS

This study, limited by a small number of subjects, suggests that one-fifth of Caucasians admitted to a state hospital in Kentucky had genotypes associated with extremes in CYP2D6 activity that may have affected their response to CYP2D6 medications.