My former SciBling David Dobbs regularly posts on the SciAm Blog, usually bringing in guest contributors highlighting novel research in neuroscience. Today, he invited Charles Glatt to review an interesting study on the interaction between genes and environment in development of depression. David writes:
This week reviewer Charles Glatt reviews a study that takes this investigation a level deeper, examining how two different gene variants show their power — or not — depending on whether a child is abused, nurtured, or both. As Glatt describes, this study, despite its grim subject, suggests promising things about the power of nurture to magnify nature’s gifts or lift its burdens.
In the study, two candidate genes identified as potentially predisposing people to depression were checked in two different environments – a nurturing one and an abusive one. Charles concludes:
As with any behavioral genetic study, one must be careful not to overinterpret these findings, because virtually no study in behavioral genetics is consistently or completely replicated. Nonetheless, some additional points about this paper can help inform us on the nature-nurture debate. First, depression scores and categorical diagnoses of depression were significantly higher in children with a history of maltreatment versus controls even before any genetic analysis was factored in. In a similar vein, the highest average depression score of any genotype category in the unabused control children was lower than the average depression score for any genotype category in the maltreated children; genes alone weren’t likely to make the child depressed, but maltreatment alone could.
These findings suggest that, at least regarding these specific polymorphisms, nurture beats nature. This conclusion will come as a relief to believers in human free will. It also argues strongly for the identification of children at risk for maltreatment and strong actions to reverse the negative effects of this experience.
Read the whole thing for details.