[Pharmacogenetics and anxiety disorders: analysis of recent findings]

Anxiety disorders are chronic disorders appearing with a high frequency in the general population and causing much distress to those suffering from them. The current common treatment consists of antidepressants, primarily from the serotonin-selective-reuptake-inhibitor (SSRI) class. However, despite the relative effectiveness of these medications the patients' responses vary widely with one third not responding at all. While we do not currently have the ability to predict who will respond positively to the medication, it is hoped that genetic research will make it possible to prospectively identify responders and thus help avoid failed treatment attempts and side-effects. The field of pharmacogenetics is divided into pharmaco-kinetics (genetic factors that influence the drug metabolism in the body) and pharmco-dynamics (genetic factors that affect the response to the drug at the level of the receptors/transporters/enzymes in the target organs). Contrary to the treatment of depression, there is little research available on the pharmacogenetics of anxiety disorders and the existing research coincides with the studies on depression. The primary pharmacogenetic-dynamic findings are related to serotonergic genes of which those with the long allele of the serotonin transporter gene (5-HTTLPR) are expected to respond positively to treatment, and the same is true regarding genetic variants of several serotonin receptors. The pharmacogenetic-kinetic findings focus on the CYP450 enzyme system. The hope is that with the progression of the pharmacogenetic research new genetic variants will be discovered which, when combined with the clinical characteristics of those suffering from anxiety disorders, will enable the development of novel treatment algorithms to be customized for each patient.