The human brain is constantly receiving and processing information about the world around us via our senses. Removing any one of these data streams can have a significant impact, both in the long term and the short term. But sometimes, this onslaught of sensory information can be too much, and we might need a break from it all. Sensory deprivation can therefore be a tool, and when used in a therapeutic way, can have real benefits.
What is sensory deprivation therapy?
The idea behind sensory deprivation therapy is to remove yourself from all the disturbances of the world in order to rest and reset.
“You’re removing the clutter and noise and distractions of daily life. Everything is stripped away. It’s just you, untethered,” integrative medicine specialist Irina Todorov told Cleveland Clinic Health Essentials.
The most common way to achieve this effect is with the use of a sensory deprivation tank. You float in salty water set at a comfortable human skin temperature, inside a dark and quiet chamber, for sessions of perhaps 30 minutes to an hour at a time.
The more technical term for this is flotation-Reduced Environmental Stimulation Therapy, or flotation-REST. It’s easy to see how spending some time in a quiet, warm, relaxing environment could make you feel good, but what about actual, measurable benefits?
What are the benefits of sensory deprivation therapy?
A study published in 2018 looked at the effect of flotation-REST on symptoms of anxiety, stress, and depression. The 50 participants in the study were diagnosed with a range of anxiety disorders, including post-traumatic stress disorder and agoraphobia, and most also had a diagnosis of depression. While it was a small study, the results did suggest that flotation-REST significantly improved people’s symptoms, and that the effects were greatest in those who had the highest anxiety scores to begin with.
Another patient group that it was hoped might benefit from this kind of therapy is those with chronic pain. However, a 2021 trial dampened expectations when it found no evidence of a long-term benefit in this group from five sessions of flotation-REST.
For mental health conditions, though, the evidence is mounting that there could be a useful role for REST, either by itself or as an adjunct to other treatments. A study published in August 2023 found that flotation-REST helped improve body image dissatisfaction and anxiety in a modest sample of inpatients being treated for anorexia nervosa.
Importantly, this treatment is fairly risk-free. That’s certainly the case when compared to medications, for example, which always come with a risk of side effects. A recent preprint, which is yet to be peer-reviewed, concluded that there were “no serious adverse events” linked to repeated sessions of flotation-REST, and that the treatment seems to be “feasible, well-tolerated, and safe in anxious and depressed individuals.”
It’s clearly too early to say whether REST as a standalone treatment might have a transformative effect on someone suffering from a severe mental illness, but given the safety profile, it may be a good, low-risk option for people to try out as part of a package of treatment.
What’s behind this? The role of interoception
Besides the obvious effect of giving you an opportunity to relax and drift away in a warm bath of tranquility, one of the theories as to why flotation-REST may have an anti-anxiety effect comes down to a peculiar phenomenon that is sometimes referred to as the “sixth sense” (although that’s not always easy to define).
Interoception is the sensing of internal signals within one’s own body. We’re talking about things like being able to hear your own heartbeat, and if that thought makes you shudder then that’s absolutely fair. The brain generally filters out these kinds of sensations as they’re just not useful to us – no one needs to be distracted by the constant lub-dub of their ticker while trying to get through the day.
However, having the ability to tap into interoceptive signals can be a good thing. In humans, awareness of one’s own heartbeat has been linked to increased empathy and a strong sense of self. And crucially, difficulties around correctly interpreting bodily sensations, particularly interoceptive signals from the heart, have been linked to anxiety disorders.
Being in an environment free of external stimuli, like a flotation tank, can make you more aware of the sensory signals coming from within your own body. For someone with an anxiety disorder, who may already be hypervigilant about any changes or potential danger signals in their insides, this might sound like the absolute worst place to be – but research has shown that, paradoxically, it can have a beneficial effect.
“First, the float environment elicited a relaxation response that was evident both physiologically (via reduced [blood pressure]) and psychologically (via reduced levels of state anxiety and muscle tension and increased levels of relaxation and serenity),” explained the authors of a 2018 study.
“Second, with regard to interoception, the data suggest that being immersed in an environment lacking exteroceptive sensation does seem to alter the experience of interoceptive sensation, leading present moment visceral sensations to emerge at the center of conscious experience during Floatation-REST.”
Addressing the apparent paradox, the authors cited a theory put forth by Joseph Wolpe in the 1950s. It holds that it’s impossible to feel both anxious and relaxed at the same time, so putting someone in a state of relaxation – such as that achieved by floating in a dark and quiet chamber – can desensitize them to things that would normally provoke their anxiety – in this case, bodily sensations.
An interesting theory, and one that could point to a long-term benefit of repeated flotation-REST for anxiety sufferers. Research into the role of interoception in other mental health disorders has continued, and more large-scale studies will be needed to know for sure what the benefits of this treatment could be. However, it’s fascinating to think that placing anxious individuals in a situation that sounds, on the face of it, like it would amplify their symptoms, could be the very thing that helps them.
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The content of this article is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of qualified health providers with questions you may have regarding medical conditions.