On a summer’s day in 1962, a year after the building of the Berlin Wall, three men in grey trenchcoats interrupted a German lesson at a secondary school in Mahlow, on the southern outskirts of the East German capital. One of them pointed a finger at 14-year-old Regina Herrmann and beckoned her to leave the classroom.

The men informed Herrmann that the ruling Socialist Unity party considered her father an enemy of the state, a “capitalist exploiter”, because he ran his own business, a hairdressing salon. In the old system, they said, bourgeois offspring like her could have counted on a university education. No more. She would not be allowed to continue attending a school in the socialist one-party state, and could bury her dreams of becoming a doctor right here and now.

In the coming months and years, Herrmann often had the feeling she was being followed. Men were always on her heels, she recalls, “like a shadow”. In her town, there were suddenly rumours that she was a Flittchen, an easy girl. Working at her father’s salon, men would make lewd comments or touch her inappropriately; twice, at a funfair and on a night bus, men tried to rape her.

Facebook Twitter Pinterest Regina Herrmann in Zurich, Switzerland, after her escape from the GDR. Photograph: Adam Berry/ Getty Images

It was only after the fall of the Berlin Wall in 1989 that Regina Herrmann found in the Stasi archives documents in which the German Democratic Republic’s secret police instructed five unofficial collaborators to target her in bars and nightclubs: “It is well known,” the file said, that Herrmann “likes to dance and is happy for her dance partners to invite her to the bar afterwards.”

As Germany gears up to celebrate 30 years since the end of the Iron Curtain this Saturday, Herrmann is one of thousands of victims of the GDR’s regime who have, until now, been denied access to support schemes because many officials in a reunified Germany are still ignorant of the covert techniques the socialist state employed to intimidate and subjugate its citizens.

Article 17 of the treaty that sealed the reunification of East and West Germany promised that victims of politically motivated measures would be entitled to “appropriate compensation”.

But whenever Herrmann has tried to find legal ways to access such funds, her applications were dismissed for lack of clear evidence. In Frankfurt in the old west, where she has settled, one official even suggested she move back to the east, where the bureaucratic system would be more sympathetic to her plight.

Now aged 72, she still works as a receptionist at a security firm, to top up her €1,073 (£923) per month old-age pension. “I’ve never wanted to go begging for benefits,” she says. “I’ve always tried to worker harder than my colleagues, to prove that I am able to.” A 2011 medical certificate diagnosed Herrmann with an addictive relationship to physical labour. “Ever since I was marched out of that classroom, I have had the feeling I needed to prove something.”

Punk persecution: how East Germany cracked down on alternative lifestyles - in pictures Read more

In the early years of the Soviet satellite state, political dissidents were mainly suppressed via official legal channels. After the building of the wall, however, the state tried to clean up its image, declaring its commitment to human rights by signing the 1972 Basic Treaty with West Germany and the 1975 Helsinki accords. As a result, any moves against real or imaginary enemies of the socialist state now needed to take place “silently”.

A 1976 directive by the head of the Stasi, Erich Mielke, proposes a catalogue of methods of psychological warfare called Zersetzung – a pseudo-scientific term for what would now be called gaslighting, literally meaning “biodegradation”. Enemies of the state, Mielke instructed, should have their reputation “systematically discredited” by spreading “untrue” but “credible, non-refutable” rumours. To destroy their enemies’ self-confidence, the Stasi would “systematically organise professional and social disappointments”.

Facebook Twitter Pinterest ‘No country likes to hear from the victims of its history’: Annegret Gollin was prevented from pursuing a career by the Stasi. Photograph: Adam Berry/ Getty Images

From a post-wall perspective, the reasons why East German citizens could be subjected to Zersetzung can sound absurd. In the case of Annegret Gollin, from Neubrandenburg, it was enough for her teenage self to wear sandals and flared jeans, and enjoy hitchhiking – a largely symbolic act of rebellion in a small state where public transport was cheap and motorways far and few between.

Hitchhikers were one of a number of “negative decadent” youth movements – including punks, rockers, goths and New Romantics – the Stasi believed to be part of a concerted western effort to undermine East German morale. After the secret police noticed Gollin hanging out with what was supposedly the wrong crowd at a blues festival, it developed a plan to systematically isolate the 18-year-old among her friends and family and frustrate her aspiration to become a bookseller, culminating in a 20-month prison sentence for “public vilification of an organ of the state”, after she drunkenly swore at a man she believed to be a spy.

After reunification, Gollin found a job as a tour guide at the German chancellery. Combined with a €300-per-month pension for East Germans who spent more than 180 days in prison, the 63-year-old has an income of about €1,400 per month – but is terrified about how she will make ends meet after retirement.

Annegret Gollin (front, far right) with fellow hitchhikers in Jena, East Germany, 1975. Photograph: Annegret Gollin

In a reunified German state, former employees of the Stasi continue to draw relatively generous public-sector pensions. Many of their victims, on the other hand, are struggling to prove to authorities that they could have found regular employment if the state hadn’t stopped them.

“I feel like I’ve been shafted twice,” Gollin says. “Every society has the same problem: no country likes to hear from the victims of its history. People want their societies to be made up of healthy people – we are not healthy.”

A new law, which is likely to be approved by the upper house of Germany’s parliament on Friday, is designed to facilitate access to further support payments, including a one-off payment of €1,500 for victims of Zersetzung and financial adjustments for those whose career aspirations were derailed for political reasons.

Victims’ associations have welcomed the new legislation, and Gollin has realistic hopes that her life could improve as a result: her Stasi files include a flowchart of Zersetzung measures against her, as well as proof that the secret police made a library deny her a position as an apprentice on false pretences.

Others will be less lucky, however. Johannes Wasmuth, a Munich-based lawyer whom the German government consulted as an expert witness on the matter, says the new law is a haphazard patchwork that doesn’t address the real dilemma at the heart of the victims’ situation.

Facebook Twitter Pinterest Frank Metzing has lived on disability benefits since 2005 due to his treatment by the Stasi. Photograph: Thomas Niedermueller/Getty

“The Stasi wasn’t stupid,” he says. “They followed the old Stalinist tactic of camouflaging the injustices they practised.” In most cases, he predicts, courts will continue to throw out applications because victims will struggle to offer concrete proof they had been subjected to psychological warfare.

Frank Metzing, from Aschersleben in Saxony-Anhalt, had received top grades at school and set his eyes on a career as a doctor. After three years training as a medical assistant, he applied for a place at the Martin Luther University in Halle, only to be denied a place. The reasons for his rejection, he claims to have been told by one of the people involved in the interview process, were his Christian faith and membership of the East German branch of the Christian Democratic Union.

Frank Metzing’s leg pokes out of his hiding place after being discovered on a train from Prague to Nuremberg in May 1983. Photograph: Frank Metzing

In May 1983, he tried to leave East Germany as a stowaway on a train from Prague to Nuremberg. One stop before crossing the border, he heard a knock on the door of his hiding place above the toilet. During the 16-month prison stint that followed, he was subjected to severe abuse and intimidation.

After he was bought out by the West German government in 1984 (a common practice), he tried to finally embark on his medical degree. But suffering from insomnia and panic attacks, he struggled to complete basic tasks. “I couldn’t concentrate. It was a catastrophe.”

Living on disability benefits since 2005, he has spent almost 15 years fighting legal battles to be paid a pension equivalent to the profession he lost out on. Courts have repeatedly dismissed his claims, saying they have no proof that he lost out on a career as a doctor for political reasons, rather because there were limited amount of places available for such a degree in the cash-strapped state.

Facebook Twitter Pinterest Astrid Giebson’s parents were arrested when she was 13 for planning to escape to the west. Photograph: Adam Berry/ Getty Images

Thirty-five years after his transfer to the west, he wrote in a letter to the authorities this year that he was “facing a legal chaos that makes such mockery of the rule of law […] I may as well as have stayed in the GDR”.

Worse still for many victims, key documents required by courts as proof of their treatment by the Stasi might not have survived the mass destruction of paperwork in the dying days of the republic.

Facebook Twitter Pinterest Astrid Giebson with her mother and father in 1980. Photograph: Adam Berry/ Getty Images

Astrid Giebson, from Berlin’s Oberschöneweide district, was only 13 when she returned from school in October 1962 to find that her mother and father had been arrested for planning to escape to the west. With both parents in prison, she was put into care with a relative seen as loyal to the ruling party, but was bullied by teachers at school and barred from pursuing her wish to become an interior decorator.

Giebson eventually managed to escape to West Germany in 1981, but efforts to get authorities to recognise her plight have ended in frustration. For the last three years, she has waited for a court to respond to her request for compensation. The last time she got a response, she was told she needed to show her juvenile records. But when she contacted her local authority, they drew a blank – her files had been lost. “It’s a fiasco,” she said. “We’re being made a mockery of.”

If lawmakers had really wanted to help victims, said the lawyer Wasmuth, they could have reversed the burden of proof, so that courts have to find evidence that individuals who found themselves in the Stasi’s crosshairs weren’t subjected to Zersetzung methods rather than vice versa.

“After the Nazi era, we in Germany had a problem with judges who didn’t recognise the injustice that had been meted out,” he added. “The situation for Stasi victims now isn’t dissimilar.”