Collectivistic cultures, which promote social harmony over individuality, protect people who are genetically predisposed to depression from experiencing the condition. So says a study published today in the journal Proceedings of the Royal Society B, which looks at how genes and environment can evolve together.
People living in individualistic cultures such as Western societies are more likely to suffer from a genetic tendency for depression than people in Eastern cultures, despite fewer people carrying the specific 'depression gene' being studied, say psychologists Joan Chiao and Katherine Blizinsky from Northwestern University. The research supports the idea that depression can result from both genes and the environment, and an interaction of the two.
The support offered by a collectivist attitude, "seems to buffer vulnerable individuals from the environmental risks or stressors that serve as triggers to depressive episodes," argues Chiao.
In Western populations, people who carry the short version of the serotonin transporter gene (STG) tend to suffer major depressive episodes when they experience a number of life stressors. The researchers examined data from 29 countries to measure genetic frequency of STG, as well as carrying out cultural psychology research to determine how collectivistic the countries were.
Individualistic cultures are defined as those that encourage thinking of people as independent of the others, and promote self expression and the pursuit of individuality over group goals, say the authors. By contrast, collectivist cultures encourage people to be thought of as connected to one another and favour maintenance of social harmony over assertion of individuality.
East Asian nations are typically more collectivist than Western societies, a finding which is corroborated by previous research. The research also showed a disproportionately high predisposition to depression in these nations than in more individualistic societies. Surprisingly, however, the study revealed that in collectivist nations such as East Asia, where almost 80 percent of the population is genetically susceptible to depression, the actual prevalence of depression was found to be significantly lower than in more individualistic nations such as the United States.
The study sheds new light on which treatments for depression are likely to prove effective, and suggests that culture-based treatments could be one approach.
"We need to move away from quick and dirty methods of treatment for depression, especially for those genetically susceptible to developing mental illness," says Chiao.