The researchers found "blunted cortisol responses to stress in bullied twins in comparison with their non-bullied co-twins." Thus, the victims were inhibited in having a normal reaction to the stress of being bullied. That difference could not be attributed to genetic differences, because they were identical twins. Nor could it be blamed on different family environments, because both twins were raised in the same conditions. The difference, the researchers concluded, came from changes in gene expression through epigenetics that left the victims less responsive to stress.
"The victims were not reacting physiologically to stress," Ouellet-Morin said in the interview. "The non-bullied twins showed the normal response, which is secreting the stress hormone while under stress." That failure to deal normally with the stress could have left them less resilient, and more prone to mental and social problems, she suggested.
The researchers conclude that the difference resulted entirely from bullying.
"This hypothesis is consistent with accumulating evidence, mainly derived from animal studies, showing that epigenetic remodeling represents a mechanism by which adverse experiences disrupt reactivity to stress and health," the study adds.
The bottom line here is that bullying must be taken very seriously, she said, but there is reason to hope that the effect doesn't have to be permanent.
"If we accept the idea suggested by this study," she said, "that social environment can change DNA manipulation that is important for stress reactivity and mood regulation, then if we change that environment, if we make sure the victims are not victimized anymore, or if we give them the proper resources to cope better with the situation and get on with their lives, then we have the possibility of reversing what we are observing right now."
Maybe there is light at the end of this very dark tunnel.