The nightmares about riot police began in December, when the “Hong Kong Hermit”, a prolific social media activist at the forefront of the Chinese-ruled city’s seven month pro-democracy movement, started shouting out in his sleep.

The affable Hong Kong-based Brit – who asked to remain anonymous – has drawn a huge Twitter following through his witty commentary and detailed filming of the protest movement, relaying the story of the anti-government demonstrations to a global audience.

But he admits the pressures of 50 hours a week online, on top of facing tear gas and rubber bullets on the streets, have taken a mental toll. “It’s a feeling of being on a hair trigger all the time,” he said.

“Everyone is exhausted and it’s on all levels of all people. Everyone has it in their own different ways. You’ve got dreams, mental and physical exhaustion and this sense that you can’t make any plans for the future.”

On Friday, a new study by the University of Hong Kong published in the Lancet medical journal, revealed that around a third of adults in Hong Kong reported symptoms of post-traumatic stress disorder (PTSD) during the often-violent social unrest.

The number was six times higher than four years ago and levels of depression are also reportedly comparable to conflict zones.