In 2013, neuroscientist John Cacioppo recorded a video for the AARP about overcoming loneliness. John, a leading researcher in social neuroscience, talked about the loneliness from losing a spouse: “It can feel like the end of the world.”

Those words would prove to be painfully insightful for his wife Stephanie Cacioppo, also a neuroscientist and John’s colleague at the University of Chicago’s Center for Cognitive and Social Neuroscience. John died suddenly in March. Cacioppo and her late husband had been together since 2011, when they met at a conference. Until John’s death, the couple worked in the same office , primarily focusing on how social interaction, or lack thereof, can be detrimental to physical and mental health.

When John died, Stephanie applied their research to her own life.

“I’m the living proof of my science, how we can recover from loneliness,” she told The Daily Beast. “Ninety days ago I never thought I would survive and now, thanks to sports and social support, I can smile and have a taste for life again. It’s really interesting how the whole thing works.”

Like many ailments, loneliness is not easily defined. And recovering from loneliness is not simple—far from it.

“First of all, you have to understand what it means to be lonely,” Stephanie Cacioppo said. “It’s not necessarily being alone. One can feel lonely in a crowd or in a marriage. Being lonely is a subjective feeling of being disconnected from others. The mind is the main social organ that can make you feel either isolated from others or connected to others and so lonely people, as a consequence, don’t see reality as it is but how they think it is.”

As a result, she explained, there’s an avoidance paradox: lonely people perceive a socially threatening environment while simultaneously feeling the need to connect with others.

Perhaps it’s that more people are paying attention to loneliness or simply that loneliness is being researched more seriously than ever, but some say there’s a loneliness epidemic among us. Millennials are forming co-living organizations to combat loneliness, the United Kingdom’s Prime Minister Theresa May announced a loneliness minister, and Australia organized a Coalition to End Loneliness.

All of this makes sense when you look at the research. A report from Cigna that studied 20,000 people resulted in nearly half of respondents saying they sometimes or always felt alone. And there’s data to back up how loneliness can be bad for your heart, can increase inflammation, can raise blood pressure, and can even cause early death.

Julianne Holt-Lunstad, a Brigham Young University psychology professor who studies loneliness and its connection to poor health and premature death, told The Daily Beast that most don’t realize how much loneliness can negatively affect overall health.

“People have this perception that if you’re lonely or isolated, it’s bad for you, but once you have friends then you’re okay,” Holt-Lundstad said. “In actuality, there’s no evidence that it’s just the extreme end that’s at risk and that everyone else is just fine. In reality, we’re all somewhere along that continuum. Of course, people at the extreme low end are at greater risk but it’s something that applies to everybody.”

Loneliness, she said, is something that needs to be tended to constantly and should be taken as seriously as physical inactivity and obesity.

“I argue that we need to take this just as seriously for our health and that just as we need to make time in our busy lives to be physically active, we need to make time to be socially active,” she said.

David Austern, a clinical psychologist in the New York University’s Langone Department of Psychiatry, works in a military clinic doing pro-bono work for active military members, veterans and their families.

“Loneliness comes up a great amount,” he told The Daily Beast, but it’s not thought of by patients as a specific diagnosis or problem they’re facing. “No one has called us up and said, ‘I want treatment to loneliness.’ It’s thought of as an additional symptom.”

“ Loneliness is something that needs to be tended to constantly and should be taken as seriously as physical inactivity and obesity. ”

Still, he said, the research in the field is promising when it comes to recognizing loneliness.

A 2016 study from the Massachusetts Institute of Technology determined where loneliness lives in the brain, at least in mice. Neurons in the dorsal raphe nucleus, or DRN, an area of the brain linked to depression, lit up with activity when mice were reintroduced to social contact after periods of isolation.

“It led us down this path of looking at isolation and how social behavior can be driven by a negative state,” Gillian Matthews, a study author who works in the Simons Center for the Social Brain at MIT, told The Daily Beast.

Kay Tye, a neuroscientist and MIT professor who worked alongside Matthews on the study, said that all motivated behaviors break down to two categories: seeking reward and avoiding punishment.

“So basically you can do anything for pain or punishment and if you think about food as an analogy, you can eat dessert or you can dig up a nasty fiber bar because you’re so unpleasantly hungry. You can seek social contact because it’s fun or you can seek it to escape this loneliness-like state. This was difficult to figure this out because no one thinks this way in our field,” Tye said.

Tye said that John Cacioppo called her to tell her he nearly fell out of his chair reading the MIT findings.

“Our most surprising finding was that the effects we saw when we changed the activity in these neurons was not consistent in all animals,” Matthews said. Which brings up a bigger question of how do different animals experience their social environment? Do all animals experience loneliness exactly the same? Our finding shows that social experience is so subjective.”

The fact that the neurons researched are in the same area of the brain as depression is an interesting factor but one that will need more time and research to fully understand. Stephanie Cacioppo said that loneliness and depression are very different and that loneliness can lead to depression. But frankly, the exact link is not yet understood.

“These neurons are near each other and it would not surprise me if they interact heavily,” Tye said. “But these neurons have been notoriously difficult to study.”

As a result, fellow MIT researcher Rebecca Saxe is in the process of seeing if what was found in mice is relevant in humans. Saxe said her team is piloting the study now and hope to start in the next couple months.

A big question in the research is how social media is affecting, or perhaps causing, this spike and attention to loneliness. A handful of studies have linked social media to loneliness, but the data is somewhat inconclusive. One study in the American Journal of Preventive Medicine found that those who spend more than two hours a day on social media had twice as much perceived isolation as those who spent 30 minutes or less on social media. Another study concluded that image-based social media platforms tended to reduce loneliness more than text based ones, that people on Snapchat and Instagram experienced less loneliness than people on Twitter.

But Holt-Lunstad said it’s really too early to know how social media and technology has affected loneliness.

“We do have good evidence that technology in general has become the primary means of social interactions now so the way in which we are interacting socially has changed dramatically and we need to really, fully understand the effects of this,” she said. “2012 was the point where more than 50 percent of people had smartphones, and if we use that as a benchmark, we need to acknowledge it’s really only been about six years so we really don’t know the long term effects of this.”

Clinicians and the healthcare industry is adapting to the research and the fact that the loneliness landscape is changing. Some practitioners have started screening patients for loneliness, specifically elderly patients who could be more at risk of social isolation.

Austern said research has dictated his treatment, using cognitive behavioral therapy to help patients suffering from loneliness. A big aspect of this is helping people understand that loneliness, as research continues to prove, is human.

“We’re not necessarily aiming to make the loneliness go away,” Austern said. “It is completely normal.”