But many others suffered greatly—particularly those who were targeted by the Stasi. Stefan Trobisch-Lütge has focused his psychiatric career on helping these people, who, he says, suffer from a variety of problems, including post-traumatic stress disorder, anxiety, and depression.

At Trobisch-Lütge’s practice here in Berlin, where haunting paintings of barbed wire and ghostlike figures line the walls, Chris Hendschke, a member of the group-counseling session, rhetorically asks the woman sitting next to him, “Friends? Do I still have friends?” He is smiling, but the truth is, he says, life in the GDR harmed his ability to trust and form lasting relationships.

In the mid-1980s, Hendschke’s life changed when he submitted an application to leave the country. That angered the Stasi, who threatened to force his wife out of her tailoring job. After a year waiting for the outcome of his application, he marched to complain at the office of human rights. The Stasi were, however, waiting for him; his intentions had been betrayed in advance. “By whom?” he says, “Who knows. Everyone knew everything about everyone else.” He was thrown in jail, and released a year and a half later in a prisoner exchange with West Germany.

The rest of the group agreed that the destruction of trust was one of the most painful legacies of their experiences in the GDR. The dense informer network meant that everyone spied on one another. Many did not find out who had informed on them until decades later, when they requested their Stasi file. One woman spoke of how she was devastated when she discovered that the man she loved was informing on her. Still reeling from this betrayal, she later found out another close friend was also spying on her. A man at the session recounted how his intention to leave the country was betrayed, and so instead of getting out, he was thrown in jail. Ten years later, on receiving his Stasi file, he found out that the person who betrayed him was his girlfriend.

“I trust only a few people I have known a long time,” Hendschke told me. “I only get to know new people with a certain distance. My life today is pretty isolated.”

Those at the group therapy session said that beyond these betrayals, the general atmosphere of the GDR meant they had to be constantly on their guard. There is evidence that this affected the whole of East German society: A 2015 study concluded that the detrimental impact of government surveillance persists and has led to lower levels of trust in post-reunification Germany. This is one of the most pernicious psychological effects of surveillance in other contexts, too, says Fisher, the psychologist.

The perception that the Stasi was all-knowing also led to self-censorship. For some, even though the dictatorship has been over for 30 years, the caution lingers—one woman at the session said she shares her political views only with people she knows well. People were socialized in a system where they had to think twice before voicing their true opinions. The fear that information can be used against you, now or in the future, can stay with you your whole life, says Neuendorf. This fear was particularly pronounced in the GDR, where the Stasi used the data it had on targets to tailor-make ways to break them and their relationships down, a process known as Zersetzung.