There is no doubt that bullying had become something really common among children and on the same lines, a recent research has warned about its serious physiological impact on children. It has been claimed that bullying badly affects stress-hormone cortisol, which controls moods and depression, thereby letting one suffer from stress.

Such victims were more likely to become vulnerable to stress and other mental problems. "Children who were bullied or maltreated showed less reactivity to stress and had more problems in social interaction and had more externalized problems, such as aggression", said Isabelle Ouellet-Morin of the University of Montreal, who is leading the research.

For the Environmental Risk Longitudinal Twin Study, the team targeted 28 sets of identical twins among a group of 2,232 children, in which one twin was made victim of bullying and other was not. It showed the difference in the levels of cortisol.

It was found during the research that those who suffered bullying could not produce serotonin, which makes them less capable to control mood swings and depression. They do equally suffer from reduced social interaction and fail to retaliate to any extreme attempt of bullying.

The research has indicated how social environment can change DNA manipulation, but still there is need of extended research on the same lines.