Floating in darkness, I forgot how old I was. It was the most curious sensation, a feeling that I could have opened the lid of the pod and emerged as a child or a much younger man into an outside world which would have reverted with me.

My experience, it turns out, was unusual but not rare.

Called time distortion, it’s one of a spectrum of unusual states of mind reported after a session of float therapy, inside what used to be called a sensory deprivation tank.

Flotation could be the best way for non-drug takers to try psychedelic transcendence

David Adam

Scientists have given this altered state of consciousness a name: aquahenosis, or unity with water.

Aquahenosis is the most important altered state you’ve never heard of: part runners’ high and part the sensation of disembodiment provoked by the psychedelic drugs ketamine and psilocybin.

“Flotation tanks and sensory deprivation are hyper-reliable elicitors of non-ordinary experiences,” says Dr Nicco Reggente, a neuroscientist at the Institute for Advanced Consciousness Studies in California.

In a study in the journal Neuroscience of Consciousness, Reggente and his colleagues analysed the types of experience reported by 75 people with anxiety or depression who tried six sessions of Flotation — REST (reduced environmental stimulation therapy).

The results suggest that floating can reliably produce some features of altered consciousness measured in studies of psychedelic drugs. That makes it a useful way to study these states and their clinical benefits.

Scientists have given this altered state of consciousness a name: aquahenosis

Getty Images

Developed in the 1950s, the technique floats people in extremely salty water, which is kept close to skin temperature. Its buoyancy is supposed to remove the sensation of a boundary between the body and the external world.

That’s the theory. For me, it was harder than expected to forget the outside world. My toes brushed the wall of the tank occasionally and I foolishly ignored the instruction not to raise my hands, managing to drip very salty water into my left eye. Unity with water has never been so painful.

About halfway through my hour-long session, I got into the swing of it. I was relaxed, I could focus on my breathing and I felt that weird ageless sensation. Weird, but pleasant, like I had total power over my memories, or was having a very easy to control dream.

Describing mental states like these is difficult. The study participants went with terms like “disembodiment”, “experience of unity” and “oceanic boundlessness”.

These might sound fun and trippy, and indeed the study authors say that flotation therapy could be the best way for non-drug takers to try some psychedelic transcendence for themselves. It could help people with psychological conditions, too. The study linked stronger feelings of oceanic boundlessness to improvements in positive mood and depression.

Aquahenosis is the most important altered state you’ve never heard of

Getty Images

But there is a possible dark side. Psychologists call the weakening of the boundary between self and non-self “ego-dissolution” and not everyone reacts well to it. “If you’re trying to grasp and hold on to what you are and what you were, it’s going to feel hellish,” Reggente says.

There is a hard edge to the research. Ketamine and psilocybin are being investigated as possible treatments for a range of psychiatric conditions and researchers want to understand how much of the benefit comes from the compounds themselves and how much from the strange, subjective mental states they produce.

Floating offers a way to separate the two. Reggente says it could eventually be used in a similar way to psychedelic-assisted therapy.

A note to classicists. Yes, aquahenosis mixes the Latin aqua (water) and the Greek henosis (unity). Sticking with Greek would give hydrohenosis, which the researchers thought sounded like a disease.