A diagnosis of bipolar disorder should not and does not come lightly. It means social stigma, years of lithium, continuous mood swings and the uncertainty of whether pharmacologic therapy will work. Lithium is the tried-and-true tested drug of choice and has been used since the 1970s for bipolar disorder. Lithium has shown to decrease acute mania, prevent episodes of mania over the long term and prevent suicidal ideations.
Recently, a genetic research study was released that demonstrated why different people have different treatment responses to lithium. Pharmacogenetics is the study of genetic differences within the metabolic pathways of pharmaceutical drugs and how the breakdown of these drugs differs among individuals depending on their genetic makeup. In other words, it tests how people metabolize drugs to determine which group of people will benefit from that certain drug. Although lithium has been on the consumer market for years, pharmacogenetic testing for this medication is relatively new and the results could be riveting.
What is bipolar disorder?
According to the Diagnostic and Statistical Manual of Mental Disorders (DSM-5), bipolar disorder is characterized by alternating highs and lows — formally known as depression and manic episodes. It truly can be a rollercoaster ride of emotions, as one week the person may be having a flight of ideas, and speaking and acting a million miles a minute, and the next week the same person can be experiencing severe depressive symptoms.
Bipolar disorder affects approximately 4 percent of the U.S. population, and the average age of onset is 21 years old. Males and females are, for the most part, affected equally. A form of personalized medicine, the ultimate goal of pharmacogenetic testing is to develop a standardized test to help physicians know which medications can benefit which patient. As previously stated, lithium is the first-line treatment of choice for this disorder.
Pharmacogenetic testing: The study
A genome-wide lithium study was developed and tested on approximately 2,000 individuals to locate the specific gene in which lithium had the best response. Researchers discovered that a single site on chromosome 21demonstrated a close relationship with lithium and it’s response in bipolar disorder. Further research was performed to test the pharmacogenetics of lithium on 73 people who have been using lithium for two years. Those individuals who carried the “lithium-responsive gene” showed a lower rate of relapse for their bipolar disorder over the two-year period compared to those individuals who did not carry the “lithium-responsive gene.” More testing must be performed to determine clinical usage for these specific findings.
Pharmacogenetic testing has been successful in initiating other pharmacological drugs in patients — specifically warfarin and carbamazepine, a blood thinner and an anti-seizure medication, respectively. This genetic testing targets individuals who have genes that are more susceptible to unwanted side effects that have been seen with the use of each of these medications. By testing a patient’s DNA before prescribing a medication, it is possible to prevent unwanted side effects and even determine the dosage amount required to treat the specific disorder, since drug metabolism is specific for each individual.
“Since Cade discovered lithium’s beneficial effects in the treatment of bipolar disorder 60 years ago, this agent has become almost synonymous with the treatment of bipolar disorder worldwide. Yet, little is known about the genetic underpinnings of lithium response or the development of side effects associated with its use,” according to the study’s authors. Therefore, combing scientific evidence, research and personalized care may be the way medicine will be practiced in future generations.
Sovereign Health of Arizona is a leading behavioral health treatment provider that treats women with addictions, mental illnesses like bipolar disorder, and co-occurring conditions. For more information, please call our 24/7 helpline.
About the author
Kristen Fuller, M.D., is a senior staff writer at the Sovereign Health Group and enjoys writing about evidence-based topics in the cutting-edge world of medicine. She is a physician and author, who also teaches, practices medicine in the urgent care setting and contributes to medicine board education. She is also an outdoor and dog enthusiast. For more information and other inquiries about this article, contact the author at firstname.lastname@example.org.
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