Liu Wei, a white-collar worker in Beijing, never imagined his investment in the stock market could shrink so fast.

The value of Liu's five stocks soared to 70,000 yuan ($11,300) in early June, nearly 50 percent more than his investment when he started putting money in the market in April.

But in mid-June, the stock market began to fall, and by Friday, the Shanghai Composite Index had plummeted nearly a quarter from its peak. Liu lost all his gains and another 20,000 yuan.

The sudden rise and fall in the stock market was unsettling, he said. (Buying stocks) "is like gambling".

"I have been feeling constant tension and worry in the past month since the stock market started to fall," he said. "All I could think of was my stocks. I would check them on my cellphone, even when I was working."

Liu said the market's plunge even damaged his relationship with his wife－sometimes they argued over which of his stocks he should sell.

Shi Chuan, a psychiatrist at Peking University Sixth Hospital, said that people should have the right attitude about setbacks and avoid excessive speculation in the stock market.

"They should properly estimate their financial situation before buying stocks," he said.

It is natural for people to become upset in stressful situations－including sudden financial losses resulting from a plunging market, he said.

"Some people cannot handle pressure and suffer more," he said. "Such people should try to learn to take sudden reversals in their stride."

With the plunge of the stock market, psychological clinics have become popular in many cities, with an increasing number of investors seeking consultations, media reports say.

Yang Lei, another psychiatrist at the hospital, said it is natural for investors who lose a lot in the stock market to display symptoms such as depression for a short time.