In a groundbreaking discovery published in the Biological Psychiatry journal, researchers at Erasmus University Medical Centre in the Netherlands and the Russian Academy of Sciences in Novosibirsk determined that a gene variant could contribute to a tendency for depression.
The NKPD1 gene, which is present in all humans, makes a protein that’s active in kidney cells. What the researchers discovered, however, is that when there’s a genetic mutation in the code for this protein, a person has a four-per-cent greater likelihood of experiencing inherited depressive symptoms, including feeling sad or lonely, experiencing poor sleep, and lack of concentration and energy.
“Further, what we have noticed is that the more deleterious the variant is predicted to be, the bigger the impact on depressive symptoms,” says Najaf Amin, lead author of the study and scientific researcher at Erasmus University.
For their research, Amin and her cohorts studied the genetic makeup of 2,000 habitants from 22 families in an isolated village in the Netherlands. Because a population that’s genetically isolated like this one leads to an upswing in rare mutations with few other variants, it makes it easier to zero in on genetic oddities.
“Depression is partly determined by genetics and partly by environmental factors,” Amin says. “The contribution of both is around 40:60.”
In addition, the study drew a connection between NKPD1 and the production of sphingolipids, a class of lipids that play a role in signal transmission and cell recognition, which are already linked to depression.
“It’s too early to tell if this will help with the treatment for depression,” Amin says. “But it can alter how psychiatrists prescribe medications, after causality is established through functional studies.”
Although the genetic predisposition to depression is well-known, there are also a host of environmental factors that shouldn’t be ignored when diagnosing depression. These include stressful life events like childhood abuse, trauma, divorce, bereavement and job loss; chronic illness including diabetes and cardiovascular disease, and the effects of certain medications.
Amin also points out that age can factor into depression, as can gender — women have a higher risk — and lack of or low education.
According to the Canadian Mental Health Association, 20 per cent of Canadians will experience mental illness in their lifetime, and eight per cent of adults will have a major depression in their lives. Youth are particularly at risk: 3.2 million teens aged 12 to 19 are at risk for developing depression, and Canada has the third highest suicide rate for teens in the industrialized world.