On April 19, 1943, Albert Hofmann became the first known human to drop LSD. The Swiss chemist had synthesized the drug five years earlier as a central nervous system stimulant, not knowing its psychedelic powers. But when he discovered what the substance was capable of, he took a dose and went for a ride on his bike to see what would happen.

What happened is he changed history. Hofmann’s account of that bike ride is not only the first documented report of a full-on acid trip, it’s also the first account of one of the hallmarks of the psychedelic state: a feeling of oneness with nature that lasts long after the drug has worn off.

“Through my LSD experience and my new picture of reality, I became aware of the wonder of creation, the magnificence of nature, and of the animal and plant kingdom,” he said in an interview in 1984. “I became very sensitive to what will happen to all this and all of us.”

Hofmann became a fervent environmentalist, and since then, similar anecdotes abound from people who have taken psychedelics. Movies and TV shows like The Trip and Six Feet Under are rife with tripping characters talking to trees or getting advice from the personification of Mother Nature, not to mention Birkenstock-clad environmentalists with a penchant for mushrooms.

But beyond the cultural trope, researchers have long suspected there was something real at play here. In a 2009 paper titled “Psychedelics and Species Connectedness,” the psychologists Stanley Krippner and David Luke hypothesized that the consumption of psychedelics creates a greater concern for ecological issues. Several other psychologists have even argued that psychedelic drugs were the catalyst for the environmental movement that sprung up in the late 1960s.

Of course, none of these theories have advanced much since LSD became illegal in the 1960s, leading the FDA to shut down all research into the potential benefits of the drug and others like it. But in the midst of today’s psychedelic renaissance, researchers are reconsidering these drugs’ potential to make us feel one with nature — and how that potential might confer therapeutic benefits.

“Psychedelics cause the boundaries between self and nature to crumble,” says Matthias Forstmann, a postdoctoral fellow at Yale University’s Mind and Development Lab. “As a consequence, you ascribe human-like traits and emotions to nature. And as a consequence of that, you feel empathy for nature. This could have beneficial effects for both the individual as well as for the environment.”

It’s likely not the feeling of connection to nature specifically that is driving away depression, but the sense of connection to everything.

Forstmann is the lead author of a recent study that looked at the relationship between people’s past experiences with classic psychedelic substances (such as LSD, psilocybin, and mescaline) and their self-reported connection to nature. The study found that people who had previous experiences with psychedelics were more likely to feel like a part of nature rather than separate from it.

The general population survey controlled for experiences with other types of psychoactive substances as well as the personality traits that can predict drug consumption and an affinity for nature. Across demographics and life experience, the study showed that psychedelic use correlates to a greater connection to the outside world.

Of course, there is the possibility that rather than psychedelics being the catalyst for an eco-mindset, it could be that people who already have a deeper connection to nature are more likely to take psychedelics. But researchers don’t think this is the case.

“[Because] the relationship we found remained significant after controlling for demographic variables, it is unlikely that the association we found can be entirely explained by a collection of personality traits stereotypically associated with psychedelic users (e.g. being of the ‘hippie’ type),” the study authors conclude.

The side effect of psychedelics that causes this sense of connection is known as ego dissolution. For this reason, some researchers think it also makes psychedelics a viable remedy for treatment-resistant depression. According to Enzo Tagliazucchi, a researcher at Goethe University Frankfurt’s Institute of Neurology, subjects in several studies who responded well to psychedelics as a depression treatment cited the “feeling of moving from a sense of disconnection from the self, from others, and from the world to a sense of connection” as the main factor in their recovery.

“One of the most salient, defining characteristics is the experience of unity with everything,” says Tagliazucchi. “It’s not specific with nature, though it can be a very strong feeling of connection with nature depending on the person, and depending on their prior beliefs.”

In other words, according to both Tagliazucchi and Forstmann, it’s likely not the feeling of connection to nature specifically that is driving away depression, but the sense of connection to everything.

However, Forstmann’s study did find that people who had used psychedelics in the past reported higher levels of pro-environmental behavior — things like recycling and buying products at the supermarket with less packaging — suggesting that such experiences can shift people’s beliefs and practices.

Before there can be conclusions around any of this, however, both Forstmann and Tagliazucchi say more research is needed — including experiments conducted outside the lab and with people without a history of mental illness. But in the meantime, Hofmann’s experience lives on, and as a new generation of psychedelic enthusiasts becomes one with nature, we may see the benefits echo throughout culture.