Young people bullied for the first time in late puberty suffer greater stress and are more likely to have an adverse reaction, a study by Matthew Newman, a Texas university psychologist, found.
Rather than stand up to the bullies they are likely to become withdrawn, attempt to avoid stressful situations and spend time plotting revenge.
Children who are bullied earlier are more likely to be aggressive when provoked but suffer fewer adverse long-term affects such as depression and violent behaviour in adulthood.
The study, based on interviews with almost 1,500 college students, showed that children with good support networks of family and friends suffer less when bullied.
It also found differences in the way boys and girls respond to bullying.
Girls tended to react aggressively after being provoked but boys were more likely to turn to drink.
Men who had been bullied late in puberty were more than twice as likely to flee from such situations as adults.
Mr Newman admitted the results were surprising: "Older children might be expected to cope better with being bullied (but) the effect was most prominent when the bullying happens late on in puberty.
"Children who are bullied earlier in puberty may be better prepared to cope with the more stressful experience of later victimisation and so suffer fewer consequences in adulthood," he said.
The findings were presented to the Society for Neuroscience meeting in San Diego and are expected to be published next year.