By Marc Bertucco, published on March 1, 2001 - last reviewed on June 14, 2012
Despite recent advances in human genetic research, predicting and treating psychological disorders through genetic means remains largely theoretical. Currently, the U.S. Department of Energy (DOE) and National Institutes of Health's Human Genome Project hopes to complete a detailed "road map" of the human genome by 2003, and a nearly complete working draft is scheduled for publication in February 2001. "We're creating a resource that thousands of scientists can then use to do the research they want to do," says Daniel Drell, Ph.D., of the DOE Office of Biological and Environmental Research.
Approximately 100 genes are currently used for diagnosis, but the human genome has an estimated 50,000 to 100,000 genes. While some genes have been known for 40 years, others connected to diseases like Alzheimer's were only recently discovered and so are more controversial. For example, every human has ApoE, the so-called Alzheimer's gene. Only when there is a particular abnormality within that gene does the possibility of developing the disease exist.
In addition to these genetic uncertainties, scientists are quick to remind us of the environment's important role in making us who we are. Drell explains that while certain psychological disorders seem to run in the family, studies on identical twins have revealed that the genetic component is just one piece of a very complicated puzzle.
"If you look at the concordance rate in identical twins [for mental conditions], it is somewhere in the 50% range," Drell says. "lf it were 100% then you would say genes were responsible that's clear. But because it is in the 50% range, you have to say that while genes are important, they're not everything."
Because of these complexities, gene therapy for behavioral and emotional disorders is probably decades away, and it's also not the whole answer. "The brain and its functioning remain more complicated and more mysterious than absolutely anything else that goes on in the human body," says Drell. "[This] is going to take us a very, very, very long time."