An entrenched sense of crisis, of course, may be exactly what wall-builders hope to create.

In the summer of 1962, an East German woman suffering from a locked jaw arrived at a psychiatric clinic in Leipzig. Weeks earlier, she’d had an infected wisdom tooth removed; even so, the doctor who referred her called her condition “inexplicable.” At the clinic, she was described as despondent and excitable. Within a few months, she was suicidal.

By the late nineteen-sixties, a German psychiatrist named Dietfried Müller-Hegemann had noticed a spike in such cases. A dentist waited at the shores of the Baltic Sea for a boat that would take him to China; a civil servant claimed he was being spied on; a seamstress thought that lesbians were trailing her. Müller-Hegemann noticed that these patients, and dozens of others, had something in common—they all lived close to the Berlin Wall. In his 1973 book, he gave the syndrome a name: Mauerkrankheit, or wall disease.


The barriers in Northern Ireland had a similar goal: stanching the violence that had left thousands dead. Israeli psychologists, meanwhile, have told Leuenberger that the security barrier makes the Palestinians invisible. “It makes a problem that people don’t want to deal with go away,” she said. The murals that are sometimes painted on border walls end up deepening the effect of the mirage.

“Basically, their purpose is psychological protection,” Vamik Volkan, a Turkish Cypriot psychiatrist with a special focus on international relations, said, of border walls. (For a time, Volkan was the president of the International Society of Political Psychology.) The structures promise to answer the question, “Who are we now?” But, in this respect, Volkan went on, they are “a psychological illusion.” Often, they only emphasize and worsen the identity crises that they are meant to resolve.

An entrenched sense of crisis, of course, may be exactly what wall-builders hope to create. When she conducted her global count of border walls, Vallet found that they had been built for three main purposes: establishing peace; preventing smuggling and terrorism; and stopping immigration.