Why are there 10,000 human brains in a warehouse in Denmark?

5,500 brains of people with dementia, 1,400 belonging to people with schizophrenia, 300 of men and women who suffered from depression... And so on, up to a total of 9,479 brains. The image shows a brain warehouse in the basement of the University of South Denmark (Syddansk Universitet).

Mental health is a relevant issue in Denmark. According to a 2014 study, one in three Danes receives treatment for a mental health disorder in their lifetime. And before the schemes of current psychology and psychiatry broke out, all mental ailments were attributed to brain problems.

Before science advanced and as doctors had little knowledge of these disorders, questionable treatments like electroshock and lobotomies (destroying a part of the patient's frontal lobe) were common.

So, at the end of the Second World War, two Danish doctors had an idea that might be valuable for science but of dubious ethics: save the brains of patients who died in psychiatric hospitals and keep them.

According to CNN, the Nordic country reportedly held the horrific record for most lobotomies per capita between the 1940s and 1980s, when the brains were collected.

The collection started n 1945 when the Risskov Institute of Brain Pathology was born. It had the most extensive collection of brains worldwide.

The goal of this project was simple: store these brains, analyze them to determine what had happened to their owners, and hopefully find cures for mental ailments.

From then until 1980, brains that fit specific profiles were collected and stored in an eerie row of shelves in an underground warehouse. In frail yellow buckets laid the brains of half of all psychiatric patients in Denmark who died between 1945 and 1982, according to a CNN recollection.

Despite the moral dilemma, the brain-collection work was meticulous and professional. After each autopsy, the brain was extracted, examined, and kept with precise annotations in the 'Brain Diaries.'

For over forty years, hospitals from all over the country sent their brains to this basement, which, in most cases, were cut for better preservation in a formaldehyde solution. Others, directly, were kept without any manipulation.

The project was stopped in 1982 when the head of the brain bank, Knud Aage Lorentzen, retired. Nobody took his place, and the collection has sat untouched in basement since then.

According to CNN, after Doctor Lorentzen's retirement, the brains sat untouched until the 1990s when the Danish public got wind of the collection. A debate arose: what to do with almost 10,000 human brains, mainly obtained without the consent of their rightful owners?

The Danish Ethics Council gave the green light to use tissues for scientific research even without having permission from relatives in 1991, while Denmark’s national association for psychiatric health (SIND) asked for the brains to be buried, sparking what CNN called one of the first significant ethical science debates in Denmark.

It lasted until 2006 when the Council of Ethics went against the public debate and finally approved using the brains for research—this time with the support of the SIND. In 2017, the collection was transferred to its current location at the University of South Denmark (in the photo, the campus).

Experts agree that there is scientific value in this collection of brains and the many annotations have been made by scientists over several decades.

Martin Wirenfeldt Nielsen, current director of the collection, told the BBC how detailed the information on each brain was: "We know who they were, where they were born, when they died, their diagnoses, and the reports of postmortem neuropathological examinations."

"One of the great values is that there are brains so old that they were removed from patients who were not given antipsychotic drugs. That means you can compare those old brains with recent brains to see which brain changes those drugs cause," Knud Kristensen, president of the Danish National Association for Mental Health, explained to BBC News.

Perhaps not every mental health problem has a strictly cerebral origin. Still, the truth is that recent research does show that dementia, schizophrenia, or even depression can be cured by acting on some parts of the brain. And this Danish collection can be an essential element to advance in that line.