Bullying in childhood gets media coverage and attention. On the other hand,the impact for adults who endured bullying in childhood and adults who now recognise that they were in fact bullies when in school get very little media attention. Understandably there is a psychological impact of bullying but recent studies have show that there is the possibility of physical illness in later life.
In a 2014 study by Kings college London, they found that the impact of childhood bullying was still evident after 40 years. http://www.kcl.ac.uk/ioppn/news/records/2014/April/Impact-of-childhood-bullying-still-evident-after-40-years.aspx
On the other hand, some adults have reported low self esteem and guilt after being challenged as a bully by former school friends who went on to tell them the impact of the bullying. Some of these adults who were challenged as bullies reported they had just been joking to gain popularity with other students – albeit at another students expense. This would tie in with Rodkin, 2011 research who found that many bullies were popular with other students and staff who could not believe the reports of bullying.
Ref:Bullying–And the Power of Peers.PC Rodkin – Educational Leadership, 2011 – ERIC