Genes Affect Response to Antidepressants

The old adage, ?one size fits all? appears not to apply to apply to medicines used to treat depression. In a report published in the Journal of the American Medical Association, it appears that one?s genetic makeup can influence the response to antidepressants, such as Prozac. Depression is a persistent state of sadness, or feeling of despair that affects an individual's ability to function socially or interferes with their activities of daily living. While we all feel down from time to time, the diagnosis of clinical depression is usually made when a patient has feelings of sadness that persists for more than 2 weeks, and interferes with their abilities to function normally. In addition, many people with clinical depression report that they no longer derive enjoyment from activities that were once pleasurable. To perform their study, researchers studied the responses to 2 commonly used classes of antidepressant medicines in over 240 patients with depression. In addition, the investigators searched for variations in the genes responsible for regulating certain brain chemicals that play a role in one?s mood. The first class of anti-depressants tested was the selective selective seretonin reuptake inhibitors, or SSRIs, of which Prozac, Zoloft and Paxil are a type. The other class was the norepinepherine reuptake inhibitors or NRIs. The results showed that patients who responded to SSRIs, were 20 times more likely to have a pleomorphism ? or variation- in a gene that is responsible for transportation of the neurotransmitter, serotonin. Those who responded to NRIs, were seven times more likely to have a pleomorhism in a gene that is responsible for transportation of the neurotransmitter norepinepherine. The results suggest that genetic variations can influence the response to antidepressants. In the future, genetic testing may influence the selection of different medicines to maximize effectiveness and reduce unwanted side effects.