HONG KONG • More Hong Kongers are showing signs of depression or post-traumatic stress disorder (PTSD) than ever before amid months of increasingly violent protests, according to a decade-long study published yesterday in The Lancet medical journal.

The prevalence of "probable depression" in residents aged 18 and older has doubled since the Occupy Central movement in 2014, when demonstrators took over major roads for 79 days, the study said.

People with symptoms of PTSD rose to 32 per cent of a sample questioned between September and November last year, at the height of the unrest. That is up from just 5 per cent after Occupy - the city's last major pro-democracy movement.

The researchers from the University of Hong Kong enrolled 18,045 adults and sampled random subsets of over 1,000 people.

"One in five adults reports probable depression or suspected PTSD, which is comparable to those experiencing armed conflicts, large-scale disasters or terrorist attacks," said the researchers.

They warned that Hong Kong was "under-resourced to deal with this excess mental health burden", and said they expect hundreds of thousands more affected adults to seek outpatient support services, translating into a 12 per cent rise in demand. The report also highlighted heavy social media usage on socio-political news as being associated with symptoms of psychological distress.

Scenes, including violent confrontations between protesters and police and mass arrests, have been widely livestreamed and circulated on social platforms by news outlets and individuals alike during the demonstrations.

The pro-democracy movement, now in its seventh month, snowballed into the worst unrest since the city returned to Chinese rule in 1997 and has plunged its economy into its first recession since the global financial crisis.

The authorities are expecting to deal with difficult challenges this year, including the "worst ever" wave of layoffs and store closures.

The "depth of the devastation" inflicted on Hong Kong's economy by more than six months of anti-government protests will be seen in the coming weeks, the chief of the city's stock exchange operator said.

The warning came as Hong Kong-based companies are expected to show the scars of the sometimes violent protests that forced businesses to shut and scared away visitors over the next few weeks when they report their annual results.

"I think local listed companies with local exposure are going to take a very big hit. They already are taking a big hit," Mr Charles Li, chief executive of Hong Kong Exchanges and Clearing, said at a Reuters event on Thursday.

BLOOMBERG, REUTERS