Genetic Testing in Psychiatry
Pharmacogenetics has developed substantially in the last twenty years. In many areas of medicine, clinicians now have access to genetic information that enables them to be much more precise when individualising therapy; with treatment choice, monitoring, and dosing informed by a specific analysis of a patient’s genetic profile.
In patients with schizophrenia, several aspects of the genetic profile have been shown to be important in determining outcomes in clozapine therapy. Psychiatric Genetic Testing Ltd (PGT) has created a suite of tests based on advances in pharmacogenetic research to provide clinicians with new insights to inform the use of clozapine in individual patients.
Genetic Testing: a powerful clinical tool
Genetic analysis is the critical step that was needed to enable truly individualised treatment. The clozapine test from PGT is a leading-edge development that has the potential to transform the use of clozapine in people with refractory schizophrenia.
Our test was developed by Professor David Taylor, Director of Pharmacy and Pathology at the Maudsley Hospital in London.
The test removes much of the uncertainty that arises when using clozapine. It provides information on four key aspects of clozapine treatment:
- The likelihood of response
- The risk of agranulocytosis
- The patient’s status in respect of benign ethnic neutropenia
- The starting dose and subsequent treatment dose
An analysis of the patient’s genetic profile can remove much of the uncertainty about the use of clozapine. It can reveal the likelihood that the patient will respond, and the risk of key adverse effects. It can also provide an estimate of how quickly clozapine will be metabolised to predict what dose will be required.
The Clozapine Test
Clozapine is the only effective treatment for people with treatment-refractory schizophrenia, defined as failed treatment attempts of adequate dose and duration with two other antipsychotics. Although the value of clozapine in these situations is widely acknowledged there is still a reluctance to prescribe and usage rates vary widely. This may mean long delays before treatment-refractory patients are offered clozapine, resulting in poor outcomes, exposure to potentially hazardous antipsychotic polypharmacy, unnecessary distress for patients, and avoidable healthcare costs. This reluctance may result from the clinical uncertainties that exist with clozapine, including the likelihood of response, the risks of adverse effects, or the optimal dosing for individual patients.