The lingering effects of central planning, combined with long-term shortages of housing, especially rentals, have limited the options for many young people in Central and Eastern Europe. When Communism collapsed, for instance, residents of state-owned housing in many Communist nations were given the opportunity to buy their apartments at generously low prices, a sweet deal that their children now find they cannot duplicate.

For some, the question has become, Why bother? The conservative culture here and in other traditional nations not only encourages young people to stay under their parents’ protection until marriage, but also attaches no stigma in doing so.

“It is just a traditional thing to do here in Slovakia,” said Katarina Izsova, Mr. Izso’s mother, as she scraped out the remnants of a pot of tomato sauce into the sink. “It is not unusual. Family members help each other.”

Social scientists caution that, while there is no doubt that the level of adults living with their parents is exceptionally high in Slovakia, the exact numbers may be lower than the official record.

“Going through the process of changing the registration of your permanent residence is a problem,” said Boris Vano, an analyst at the Demographic Research Center at the Institute of Informatics and Statistics in Bratislava, the capital. “For many people, it’s not worth going through the bureaucratic hassle. It is illegal, but there are no fines.”

At the same time, a few other European countries hit hard by the 2008 recession and the ensuing euro crisis also have high percentages of adults living with their parents — 53 percent in Greece, for instance, and 49 percent in Italy.

In Central and Eastern Europe, the trend is going up. From 2007 to 2013, the number of young adults living at home in Hungary shot up by 40 percent, and by 10 percent in Slovakia.