The negative effects of childhood bullying could last even longer than previously thought, with victims having higher risk in depression, ill-health and even joblessness in their middle age, according to a British research published Friday.

A previous study covering around 1,400 participants revealed that, children bullying had a series of negative impacts on people's mental health, employment and social relationships, which could last as long as 15 years.

However, in the new study, researchers from Kings College London concluded that the negative social, physical and mental health effects of childhood bullying are still evident up to 40 years later in their middle age.

Looking at data of nearly 7,771 British children born in 1958, researchers revealed that those who had suffered bullying when they were aged 7 and 11 were still more likely to suffer from a range of health and social problems, even up to the age 50.

Those who were bullied in childhood usually have poorer mental heath and cognitive functioning at 50, and those frequently bullied were nearly twice as likely to be suffering from depression and an increased risk of anxiety disorders and developing suicidal thoughts.

They were also more likely to have lower educational levels, and men who were bullied were more likely to be jobless and earn less. Their social relationships were affected as well, with lower possibility of being in a relationship, or having good social support.

The study, which is the first to look at the effects of bullying beyond early adulthood, has been published in the American Journal of Psychiatry.

"Our study shows that the effects of bullying are still visible nearly four decades later." Dr Ryu Takizawa, lead author of the paper from KCL, said: "The impact of bullying is persistent and pervasive, with health, social and economic consequences lasting well into adulthood."