Nature and nurture contribute equally to depression

They examined five types of families with various combinations of biological or adoptive offspring

For the first time, researchers have found that the environment you’re raised in is as important as your genes in determining risk for major depression. In a large retrospective study, researchers looked at depression diagnoses among more than 2.2 million people in Sweden and their parents and found that genetic factors and household environment contributed equally to odds that the illness would be “transmitted” from parents to offspring.
 
The results — based on comparing adopted and biological offspring from both intact and broken families — contradict many previous findings from twin studies that suggested genetic predisposition plays the larger