Richard R. Johnson is the first to admit it was a bad idea.

Recently laid off from a job building trailers in Elkhart, Ind., Mr. Johnson came up a dollar short at Martin’s Supermarket last month when he went to buy a $4.99 bottle of sleep medication. So, “for some stupid reason,” he tried to shoplift it and was immediately arrested.

“I was desperate, I guess,” said Mr. Johnson, 25, who said he had never been arrested before. As the economy has weakened, shoplifting has increased, and retail security experts say the problem has grown worse this holiday season. Shoplifters are taking everything from compact discs and baby formula to gift cards and designer clothing.

Police departments across the country say that shoplifting arrests are 10 percent to 20 percent higher this year than last. The problem is probably even greater than arrest records indicate since shoplifters are often banned from stores rather than arrested.

Much of the increase has come from first-time offenders like Mr. Johnson making rash decisions in a pinch, the authorities say. But the ease with which stolen goods can be sold on the Internet has meant a bigger role for organized crime rings, which also engage in receipt fraud, fake price tagging and gift card schemes, the police and security experts say.