Retail investors, known locally as ants, were a force in a 50% stock-price surge after a virus-induced sell-off in March.
From then through May, however, those seeking help for trading-related addictive behaviour reached 214, showed data from the Korea Center on Gambling Problems. The growth rate eclipsed the overall 16% rise in calls seeking help.
The trend is a worrying sign of things to come should social distancing practices such as work-from-home become the norm, experts said, as isolated individuals have even fewer mechanisms such as peer support to check addictive behaviour.
Compulsive stock trading also lacks the social stigma that may act as a deterrent toward traditional forms of gambling, even though the stimulation behind both is similar, they said.
South Korea has not enforced any virus-busting lockdown measures, even during the height of the outbreak in the country over February and March. Nevertheless, people and businesses by and large have followed government guidelines and refrained from social gatherings and instituted work-from-home arrangements.
One such individual was 35-year-old bank employee surnamed Lee. He has been trading shares online for over a year since hearing of a friend who made a windfall through frequently buying and selling stocks based on rumour and speculation.
Though Lee has seen some success - once making a profit of several hundred thousand dollars in a single trade - increased trading time afforded by working-from-home culminated last month in him losing 1.2 billion won ($1 million) over five days.
On the insistence of his wife, he said, he subsequently sought help from a gambling addiction counsellor.
"We tend to see an influx of people seeking help after a huge market dive," said Kim Yeon-su, treatment manager at the Korea Center on Gambling Problems help centre in Seoul. "It happened with Bitcoin and now it's happening with stocks."
Active trading accounts - the bulk of which belong to retail investors - rose 2.8 million from mid-January through mid-July, versus 1.6 million in the same period last year, financial association data showed.
The surge was reflected in the July listing of SK Biopharmaceuticals Co Ltd, where each share on offer for retail investors attracted 323 prospective buyers whose down-payments totalled 31 trillion won. The successful buyers saw their investment more than quintuple in four days.
Investor message boards on South Korea's dominant internet search portal see high traffic throughout trading hours with posts such as, "I want to become a king ant" and "I was robbed today as usual", plus discussion of obscure stocks and preferred shares.
Mental health experts said trading can become high-stakes gambling, with little to hold back the trader when they can trade easily online at home and often on credit.
"Some of these people are buying, selling, buying, selling... To become a gambler, you need immediate stimulation to the brain. Invest in stable things, wait three months - they don't do this," said psychiatrist Shin Young-chul at the Kangbuk Samsung Hospital.
"For a person for whom 400 million won goes back and forth in a day, can they stay engaged in their job that earns 2 million won a month?"
($1 = 1,203.1000 won)
By Joyce Lee