An extensive DNA study, involving almost half a million people of European origin, has uncovered fifteen regions in the human genome associated with the development of depression.

Inside these areas, scientists revealed seventeen genetic variations that could lead to depression. The study was carried out by researchers from the Massachusetts General Hospital, Pfizer Pharmaceuticals and 23andMe, a privately owned personal genomics and biotechnology company that made the study possible in the first place, as the genetic profiles used in the investigation came from its database.

Screening consists of checking a seemingly healthy person for signs of hidden depression. Image credit: Stat News

How many of us can be depressed?

Roughly 460,000 people consented to have their genetic profiles used in the research, and provided additional data through a questionnaire, answering questions such as whether or not they were depressed or had seen a doctor for symptoms of depression, or if they had never been diagnosed with the disease in the first place.

The first group was comprised of a total of 300,000 individuals. Of these, 75,607 individuals reported a clinical diagnosis of depression or were receiving treatment for the condition.

The rest was used as a ‘control group’. By analyzing the frequency of common genetic variations in the first group compared to those in the second group, the team could find the ‘genomic’ regions linked with depression, which overlaps with the regions previously linked to schizophrenia, epilepsy, bipolar disorder and intellectual disability.

The findings were then validated with further analysis of another group of roughly, 150,000 individuals; this time involving 45,733 people who reported depression and 106,354 who did not.

What the study says about depression

The study shows the biology of the disease, and it can lead to a deeper understanding of how genetic and environmental factors interact with each other, potentially opening the gates for better, more accurate treatments and medications.

The confirmation of depression being an illness of the brain with its biology could also lead to lessened stigma among the general population.

The research also shows the value of genetic companies. As mentioned before, 23AndMe’s involvement and cooperation allowed to have a large sample to work with; bigger than many before.

There are some caveats

While the data from 23AndMe is quite vast, it’s not perfect. The consumers send saliva samples to have their genetic profiles created, which is thought to be less reliable than blood because of the self-degrading enzymes found in it. The company also doesn’t run a full genome sequence, just a few key parts of it.

Jonathan Flint, from the University of California, also warns about using data based on self-reports of the diagnosis; many people with depression fail to get diagnosed, and many who do not suffer the symptoms of the disease. He argues that they might be identifying something more to do with help-seeking behavior, rather than with depression, according to The Guardian.

Nonetheless, the research is still valuable, and will hopefully lead to further developments in the treatment, diagnostic, and maybe even a cure, in the future.

Sources: The Guardian