For years, Maggie May, a resident of Arkansas, struggled with atypical anorexia nervosa. Traditional therapies failed to address her severe food restriction and distorted body image. In 2024, she enrolled in an experimental trial involving sensory deprivation: floating in dark, soundproof water heated to skin temperature. The goal wasn’t relaxation, but inward focus—feeling her heartbeat, breathing, and other internal signals. This reflects a growing understanding in psychiatry that mental illness may stem from a miscalibration of our interoception, the ability to sense our body’s internal state.
What is Interoception?
Interoception isn’t new; the idea that emotions arise from bodily reactions dates back to the 1880s with the James-Lange theory. However, recent neuroscience confirms that this “sixth sense” – distinct from sight, sound, or touch – is vital for mental well-being. Some people are naturally better at it than others, and life events can strengthen or weaken this skill. Disrupted interoception may drive conditions like anorexia; by suppressing internal signals, sufferers over-rely on external cues (like appearance), fueling distorted body perception.
From Flotation Tanks to Gut Feelings
Researchers now believe interoceptive problems contribute to anxiety, PTSD, borderline personality disorder, and even schizophrenia. Studies show that people with mental illness often report physical symptoms – racing heartbeats, altered breathing, appetite changes – that clinicians have long noted. Therapies targeting this inner sense are emerging. Flotation-REST, the decades-old technique used with Maggie May, aims to blunt external stimuli so internal signals become stronger.
But interoception isn’t just about the heart. Breathing patterns, gut rhythms, and other visceral signals also influence emotional reactions. Experiments show that breathing rate affects pain perception, and manipulating gut signals can alter disgust responses. This suggests that the mind-body connection isn’t just philosophical; it’s a measurable neurological process.
The Brain’s Prediction Problem
One theory is that disruptions arise from faulty brain predictions. Like other senses, interoception feeds information to the brain, which constantly anticipates internal states. If the brain misinterprets these signals (e.g., assuming a normal heart rate is a panic attack), it can trigger negative psychological effects. This is especially problematic because internal signals are ambiguous, relying heavily on prior experience and learned associations.
Measuring the Immeasurable
Research into interoception faces hurdles. Early studies relied on subjective pulse counting, which proved unreliable (people often report what they think their heart rate should be, not what it actually is). Newer methods are emerging: heart-rate discrimination tasks, breathing-resistance tests, and brain imaging (measuring heartbeat-evoked potentials) offer more precise data.
The Future of Interoception Research
These studies reveal that interoceptive skills don’t translate across bodily functions. Someone good at sensing their heartbeat may struggle with breath awareness. This complicates the search for universal patterns, suggesting that different mental illnesses may involve disruptions in specific interoceptive systems.
Ultimately, the body and mind are inextricably intertwined. The rise of interoception research signals a shift in mental health treatment: acknowledging that psychological disorders aren’t just “in the head,” but rooted in the complex interplay between brain, body, and environment.
