Genetic Tests in Medical Treatment Not Yet Useful -- MEDICA - World Forum for Medicine

The report found that tests evaluating differences in genes belonging to the Cytochrome P450, or CYP450, family that affect the rate at which a person metabolizes SSRIs are largely accurate. However, the researchers did not find any evidence that such tests led to improved patient outcomes or had an impact on treatment decisions for patients with depression. The researchers noted that other genetic factors and non-genetic factors such as diet and other medical conditions may have an impact on a patient’s response to treatment.

“This report highlights how systematically reviewing scientific findings can help guide future research,” said Beth A. Collins Sharp, Ph.D., R.N., director of the Evidence-based Practice Center Program triggered by the Agency for Healthcare Research and Quality (AHRQ).

Researchers performed a comprehensive review of the literature and found no well-designed studies that evaluated clinical outcomes of tests to detect differences in genes belonging to the CYP450 family. These genes produce enzymes that break down SSRIs and many other classes of drugs. Most studies included a small number of people, did not test for all variations of the enzymes, and were poorly designed, according to the researchers. The majority of studies also reported the rate of metabolism after just one dose or were done in patients without depression - factors that do not accurately represent the long-term use of these drugs in patients with depression.

The report found a relationship between genetic differences and the occurrence of adverse effects from SSRIs in depressed patients in only two of six studies. However, the researchers concluded that all six studies were poorly designed, which limits the ability to draw conclusions about the CYP450 genes and SSRIs.; Source: Agency for Healthcare Research and Quality (AHRQ)