Stress. We all know it’s not good for you. About a decade ago, Dr. Michael Meaney’s and Dr. Moshe Szyf’s research group from McGill University made some pioneering breakthroughs in the field while examining the effects of early life stress on the epigenome of rats.

Since then the field has been booming, however most studies have focused on animal models. But recently there has been an effort to translate these results to humans.

Dr. Louise Arseneault’s group from King’s College London decided to focus their efforts on an oh so familiar early life stress: bullying. And odds are that if you’re reading this then you probably experienced it. Well, it turns out being bullied can actually lead to a wide range of mental health problems like depression and anxiety. Anyways, putting our childhood traumas aside, here are the highlights of Dr. Arseneault’s latest research:

They observed increased DNA methylation of SERT , a serotonin transporter gene, while comparing a bullied identical twin to their ‘more popular’, non-bullied (discordant) twin.

, a serotonin transporter gene, while comparing a bullied identical twin to their ‘more popular’, non-bullied (discordant) twin. The twin with increased SERT methylation also showed a decreased cortisol response.

methylation also showed a decreased cortisol response. Decreased cortisol responses have been previously linked to a poor stress coping strategies and are believed to play a role in many mental disorders.

The biggest strength of this research is the use of multiple sets of discordant identical twins, since it allowed them to essentially eliminate genetic and shared environmental confounds, which is something hardly ever done in human studies. Ultimately, this is one of the first studies to provide longitudinal evidence that epigenetic processes are dynamic and responsive to early social environments in humans.

Read all about it in Psychological Medicine.