The unraveling of the human genome has lead to advances in determining genetic risk profiles for particular illnesses. Perhaps the best known and scientifically credible discovery is the link between the BRCA genes and the development of breast cancer.
However, when it come to assessing the risk of developing mental conditions such as bipolar, the genes responsible for most brain disorders remain unknown. Nevertheless, commercial genetic tests are now available that claim to assess your risk of developing bipolar disorder. Genetic tests for major depression and schizophrenia are also expected to reach the market soon.
The May issue of the Harvard Health Letter elaborates on the controversy.
According to the Harvard experts, one problem is that the genetics field is advancing so rapidly that it’s hard to keep up with developments, never mind figure out which ones are clinically relevant.
Most authorities also believe that psychiatric disorders develop because of the interplay between multiple genes, each exerting small effects. That makes finding the responsible genes harder. Further complicating matters, research has revealed that many healthy relatives of people with psychiatric disorders have risk genes.
Whether a person develops an illness depends on unknown ways the risk genes interact with other genes and environmental factors.
Scientists have identified perhaps thousands of candidate genes that may contribute to psychiatric conditions. But experts continue to debate which genes are actually involved. Most candidate genes fail to hold up—meaning that the association between the gene and a given illness disappears when scientists try to replicate the results. One analysis estimated that 70% to 80% of candidate genes are false positives.
Dr. Michael Miller, editor in chief of the Harvard Mental Health Letter, notes that someday it may be possible to reliably assess risk for psychiatric disorders. But at this point, the technology—and the science—is still evolving.
Source: Harvard Mental Health Letter