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Dr. Leahy is Family Psychiatric Advanced Practice Nurse and Master Clinician in Psychopharmacology, APNSolutions, LLC, Sewell, New Jersey.
The author has disclosed no potential conflicts of interest, financial or otherwise.
Exploring psychotherapeutic issues and agents in clinical practice
Unlike medical ailments, psychiatric disorders do not have easily identifiable biological markers to confirm a diagnosis. Thus, determining which psychotropic medication may be most beneficial to a patient is often reduced to trial-and-error prescribing, taking weeks to determine whether therapeutic benefit will occur and/or if side effects will persist. To date, there are no definitive laboratory tests or imaging scans that prove conclusively what disorder a patient may be experiencing. Yet, it is widely known that heredity, otherwise known as genetics, plays a role in psychiatric disorders. Family studies published by Lohoff ( 2010 ) show that among first-degree relatives, there is a two- to three-fold increase in the lifetime risk of developing major depressive disorder. Similarly, according to Smoller and Finn ( 2003 ), the heritability of bipolar disorder among twins is between 60% and 80%. With this in mind, genetic testing to assist in the selection of psychotropic medication therapies may prove beneficial to those experiencing psychiatric symptoms.
Background on Genetics
Although human beings are unique individuals, 99.9% of their genetic code is shared with other human beings, and approximately 96% of their DNA is shared with chimpanzees and approximately 60% with bananas ( National Human Genome Project, 2002 ). In addition, <10% of human beings' genetic code offers regulatory information ( Bojrab, 2013 ) on how the body and brain are supposed to think, feel, and behave. And, because only 0.1% of their DNA is unique, it is the allele , a variant form of a given gene inherited from each parent, that provides an individual's distinct differences. The genetic variants or polymorphisms are precisely what genetic testing offers to psychiatric practitioners to guide pharmacological decision making.
Genetic Testing in Psychiatric Practice
So how does the testing of patients' DNA help in the pharmacological management of psychiatric symptoms? According to Frueh et al. ( 2008 ), more than 25% of all common medications have genetic information that can be tested and used to personalize medical treatment. Genotyping of genetic variants is not a new...