Genetic testing allows individuals to submit a genetic sample to a company, which then analyzes the genes for known anomalies or other problems. The idea is that by having that information, you may be able to be more aware of potential health problems down the road. Or even stave them off before they become a problem by changing your behaviors, diet, and exercise regimen. Companies like 23andme and Navigenics provide genetic DNA testing reports that purportedly tell you your risk factors for getting not only certain medical conditions, but also mental disorders, like bipolar or attention deficit disorder.

This may work fine for some very well-defined health issues, like heart disease (although a recent government investigation into these companies’ abilities to provide even this information reliably suggests some problems). But it doesn’t work at all for any mental disorder.

Two years ago, I wrote that I thought genetic tests for mental health problems are largely scams. Today, I’m here to reaffirm that our understanding of the causes of mental disorders has progressed very little in two years. And so genetic testing for a mental disorder vulnerability is still very much suspect. It is not recommended, as I don’t see a person getting much value for their money.

Let’s take a look at bipolar disorder, one of the most serious and devastating mental disorders. A review by two National Institute of Mental Health researchers of the heritability of bipolar disorder through genes suggests a grim picture (Schulze & McMahon, 2009):

After close to a century of genetic studies, bipolar disorder is emerging as a complex (non-Mendelian) disorder with a polygenic etiology. The search for common genetic variants with small effects by GWAS will probably have to be complemented by approaches that can detect rare genetic variations with larger effects, such as copy number variants.

What this means in plain English is that bipolar disorder’s genetic components are likely to be found on many, many different genes — there is no single gene that accounts for bipolar disorder. Nor is such a gene ever likely to be found. It’s a complex, subtle interaction going on here, and one that no current genetic testing can pick up on to help you determine your susceptibility to this disorder.

So it begs the question — why do genetic testing companies even target this disorder, when they know our knowledge about the genetic causes of it is in its very infancy and can tell a single individual very little about their own personal risk factor? I don’t know. The 23andme sample report page on bipolar disorder, for instance, doesn’t mention this fact at all, until you scroll down to the very bottom of the page and you get this paragraph in obtuse language:

Scientists know that bipolar disorder has a strong genetic component, but finding variations associated with the condition has been difficult. The SNPs that have been identified, including the one reported here, explain only a fraction of the genetic contribution to the disease.

Here, let me translate, “Our data on this disorder will be useless to calculate your individual risk factor. But we’ll report it anyway, making it seem like you’re getting some sort of valuable information from our report.”

This is modern day snake oil, in my opinion. The research on the genetics of mental disorders remains very much in its infancy, yet companies are selling you hope that their DNA testing will reveal something of value to you. They do this to make their market as broad and as wide as possible, otherwise they risk not making enough money back to their investors. Regardless of the scientific validity of what they’re selling. This is a simple matter of marketing and money trumpeting the science and data.

Perhaps in a decade or two, we’ll be in a much better position to understand the genetic foundations of many common mental disorders. But as of today, that understanding remains in its infancy. And companies looking to profit off of people’s ignorance and fears about these concerns should be ashamed of themselves.

Read the full article: Navigenics, 23andMe slammed in government report