There's no genetic line between happiness, depression

It turns out, the same genes that make us prone to depression could also open us to positivity.

Elaine Fox from Oxford University and Chris Beevers from the University of Texas at Austin reviewed a number of studies. They said that there is a need to combine studies in mental health genetics with those that look at cognitive biases.

Beevers noted, "Cognitive biases are when people consistently interpret situations though particular mental 'filters,' when people have a cognitive bias that emphasises negative aspects or thoughts, they are more at risk of mental health disorders. There is a lot of research about these biases and a lot of research about genes that may make people susceptible to mental ill health. However, we suggest that it could make more sense to bring together these two areas of research."

Fox said: "If you take a gene that is linked to mental illness, and compare people who have the same genetic variant, it becomes clear that what happens to their mental health is based on their environment. We suggest that while no gene 'causes' mental ill health, some genes can make people more sensitive to the effects of their environment - for better and for worse."

"If you have those genes and are in a negative environment, you are likely to develop the negative cognitive biases that lead to mental disorders. If you have those genes but are in a supportive environment, you are likely to develop positive cognitive biases that increase your mental resilience," she added.

Fox, who is currently carrying out further research into this combined genetic and environmental effect on our mental filters, intends to see how sets of genes may affect mental health outcomes and how these are moderated by people's environments.

The study appears in the journal Molecular Psychiatry.