Tactile / Somatic hallucinations

1. Overview — What are Tactile / Somatic Hallucinations?

When people talk about “hallucinations,” most will think of hearing voices or seeing things (auditory or visual hallucinations) first. In reality, the touch system and body perception can also “hallucinate,” and that is where we use the terms:

Tactile hallucinations = hallucinations involving “cutaneous / skin-level touch”

Somatic hallucinations = hallucinations involving “internal bodily sensations / internal organs”

Both of these are experiences that feel intensely real, to the point where the person is convinced that

“This is definitely happening to my body right now,”

even though, in reality:

There is no external stimulus, and

Physical examination does not reveal any disease or abnormality that could explain the sensations.

Tactile hallucinations

These are hallucinations of touch — the brain creates a sensation of being touched even though nothing is actually touching the skin.

They usually occur at the skin or just beneath the skin, such as:

Hands, arms, legs

Scalp

Back

Or across the whole body

Common examples include:

Feeling as if insects/ants are crawling on the skin or moving back and forth under the skin (the origin of the term formication).

Feeling a light “tap” or touch on the back, even though no one is nearby.

Feeling as if someone is grabbing the arm, squeezing the shoulder, or sitting pressed up against them.

Feeling burning or stinging, like the skin has been scalded, even though there is no visible burn or redness.

Some people experience sexualized touch, for example feeling as if someone is hugging them, caressing them, or having sexual intercourse with them, even though they are physically alone.

A key point is that patients often describe:

“It really feels like something is touching me. It’s not just in my head.”

To the extent that many people scratch, claw, or injure their own skin trying to “get whatever they’re feeling out,” which can lead to abrasions, bleeding, or infections.

Somatic hallucinations

These are hallucinations of internal bodily perception (interoception).

They involve the internal organs, muscles, bones, blood, intestines, brain, or a sense of “the whole body”.

They are bizarre bodily sensations that:

Have no underlying physical disease to account for them, or

Are far too extreme to be explained by typical physical symptoms.

Examples include:

Feeling as if the intestines are being pulled, twisted, or stabbed from the inside.

Feeling as if animals, worms, insects, or some living creature is moving around in the abdomen or in the genital area.

Feeling as if the blood is boiling, flowing abnormally forcefully, or the body is “burning from the inside.”

Feeling as if the brain is being burned, squeezed, or that something is intruding into the skull.

Feeling as if the bones are shattering into pieces, even though the person can walk normally and X-rays show no abnormalities.

In older psychiatric literature, terms like:

cenesthetic / cenesthopathic hallucinations

were used to describe somatic hallucinations that are “extremely strange and difficult to describe”, especially those involving internal organs or disturbances in the sense of “the physical self as a whole body.”

For example, feeling that the body is hollow, has no organs, or that certain organs have been relocated.

A brief contrast

Tactile hallucinations

Are exteroceptive → focused on “what is felt on the skin / outside the body.”

Examples: feeling as if insects are crawling on the skin, the arm is being grabbed, or the skin is being poked.

Somatic hallucinations

Are interoceptive / visceral → focused on “what is felt from inside the body.”

Examples: twisting intestines, boiling blood, brain burning.

Clinically, both types:

Are categorized directly under hallucinations (abnormal perception without a real stimulus).

Are not just “overthinking” or “being so anxious that you feel weird in your body,” but reflect abnormal processing of sensory signals in the brain.

They are often found together with other disorders, such as:

Schizophrenia spectrum (especially cases with body-related delusions),

Mood disorders with psychotic features (depression / bipolar with psychosis),

Substance-induced psychosis from alcohol, stimulant drugs, etc.,

Delirium, dementia, epilepsy, Parkinson’s disease, alcohol withdrawal, and other neurological conditions.

Therefore, when tactile or somatic hallucinations are seen in real cases, clinicians typically view them as a “warning sign” that there may be an important underlying psychiatric or neurological disorder — rather than just a quirky, temporary symptom.

2. Core Symptoms — Key Symptom Features

If written clearly, this section becomes the main core that helps readers understand what tactile / somatic hallucinations actually feel like, how they differ from ordinary physical symptoms, and how much they disrupt patients’ lives.

2.1 Features of Tactile hallucinations — Abnormal skin-level sensations

Short definition
They are “sensations of being touched” that are generated by the brain itself, even though nothing is actually touching the skin.

Key points for description

Location of the sensation

Most often felt at the skin or just below it, such as: arms, legs, trunk, scalp, back of the neck, face, fingertips, toes.

Some people can point to the exact spot (“Right here, here, here — like something’s crawling”), while others describe it as “all over the body.”

Common types of touch sensations

Feeling as if insects/ants/tiny creatures are crawling on or under the skin (formication).

Feeling as if someone is flicking / tapping / knocking / pricking with a needle on the skin.

Feeling as if someone is holding the arm, grabbing the shoulder, putting an arm around the shoulders, holding hands, or squeezing a leg.

Feeling as if one is being stroked, hugged, kissed, or having sex, despite being alone.

Feeling burning, intense itching, or as if the skin is burning, but with no rash and no dermatological lesion that would explain it.

Quality of the sensation

Patients often describe it as:

“It feels so real,”

on the same level as when something is actually touching their skin.

Some can further specify that the sensation is:

Light / heavy / sharp / faint like a breeze, or

That it feels like it comes from a “living creature” versus an “inanimate” contact (for example, a small stone rolling on the skin versus an insect crawling).

Temporal pattern

Some cases are on-and-off, occurring multiple times a day.

Others are continuous for hours, severely disrupting sleep.

Some report that symptoms worsen at night or when lying still.

Triggers

Stress / sleep deprivation / substance use / alcohol withdrawal.

Some people say symptoms are worse when they’re alone or in quiet places → they focus more intensely on bodily sensations.

Behavioral responses

Scratching/clawing/squeezing the skin hard because they are convinced something is really there.

Various attempts to “get rid of it”, such as repeated showering, changing bed sheets frequently, washing clothes excessively.

Some go as far as using sharp objects to dig into or cut the skin to “remove the insects” → very high risk of severe infection.

Level of belief and interpretation

Some still have partial insight:

“I know it probably isn’t real, but it feels so real that I can’t help it.”

Others are 100% convinced that something is truly there → this begins to move toward delusional parasitosis (a fixed belief that one is infested with parasites/insects).

In some cases, the experiences are woven into persecutory themes, such as:

“Someone is secretly touching my body when I sleep.”
“An organization sent tiny robots to walk around inside me.”

Affective tone (emotional coloring)

Most are dominated by fear, paranoia, disgust, and extreme irritation.

If the sensation is sexualized touch, some may feel embarrassed, confused, guilty, or violated more than afraid.

In substance-induced psychosis, it often comes with severe panic, agitation, and paranoia.

Impact on daily life

Insomnia, inability to work, reluctance to leave home, social withdrawal.

High costs from repeated visits to dermatologists/other doctors, constant changes of mattresses, sheets, curtains, etc.

Strained family relationships because relatives may dismiss it as “overthinking / being mentally weak / being dirty or unclean.”

Illustrative clinical vignette

One patient said:

“It feels like hundreds of tiny ants crawl up from my feet, along my legs, all the way to my back. No matter how much I brush them off, it doesn’t go away. When I look, there’s nothing there. But the feeling is so real that I end up showering every hour.”

All of this shows why tactile hallucinations are not just ordinary itching, irritation, or skin pain. They are “touch experiences created by the brain” that carry the same weight as real touch in the patient’s subjective world.

2.2 Features of Somatic hallucinations — Abnormal internal bodily sensations

Short definition
They are “abnormal internal bodily sensations” that are intense, bizarre, and cannot be explained by any physical disease, yet the person is convinced they are genuinely happening to their organs.

Key elaboration points

Location of the sensation

They are typically felt deep inside the body, for example:

Abdomen / intestines / abdominal cavity

Chest / heart / lungs

Brain / skull

Bones / bone marrow / joints

Genital area / anus

Some people feel it as “the whole body”, such as:

“I feel like my entire body is rotting.”

Common types of sensations

Feeling as if organs are being twisted, squeezed, pulled, torn, or gouged.

Feeling as if something alive is inside — animals, worms, insects, fish, snakes.

Feeling as if solid objects or foreign bodies are embedded in the bones or tissues.

Feeling as if the blood is boiling / the heart has stopped / the brain is burning / the intestines are rotten.

Strange movement sensations, such as:

“My organs are moving on their own,”
“My bones are shifting position.”

Kinesthetic hallucinations

These are “somatic hallucinations of movement” → feeling as if:

Arms, legs, or the entire body are moving / being moved,

Even though, in reality, the body is still.

Some patients say:

“It feels like someone inside is controlling how my body moves.”

Cenesthetic / cenesthopathic hallucinations

These terms are used for somatic hallucinations that are so strange they are hard to describe, such as:

“I feel like the inside of my body is completely hollow, with no intestines, no organs.”

“I feel like my bones are melting, turning into liquid.”

“I feel like my heart has been pulled out and placed outside my chest, and an invisible hand is squeezing it constantly.”

They are often tied to nihilistic delusions or religious/somatic delusions in schizophrenia or psychotic depression.

Bizarre and hard-to-describe quality

Many patients will preface their story with something like:

“I know it sounds crazy, but this is really how it feels.”

The symptoms often clearly exceed biological plausibility, such as claiming that the liver has completely disappeared, yet the person walks and functions normally.

Level of belief

Almost everyone believes:

It is truly happening to the body,

Not “just a thought.”

If combined with delusions, they might say:

“The doctors took my organs out.”

“There’s a listening device embedded in my bones.”

“My body has rotted, my blood no longer flows, but nobody accepts the truth.”

Relation to emotional themes

They are often linked to:

Persecutory themes (being harmed, experimented on), or

Nihilistic themes (the world/self is already dead, the body is hollow, empty).

In psychotic depression, they may tie into themes of worthlessness, guilt, punishment, such as believing they are being burned from the inside as divine punishment for sins.

Impact on behavior

Visiting many different specialists and undergoing repeated tests (all normal).

Spending large amounts of money on special investigations.

Some request surgeries or removal of organs with no medical indication.

Risk of self-harm to “remove foreign objects” or to “prove that the blood no longer flows.”

Difference from real physical symptoms / panic / anxiety

Panic / anxiety: there are physical symptoms (palpitations, chest tightness, shortness of breath), but they stay within biological limits.

Somatic hallucinations / psychosis: the content is usually over-the-top, beyond physics and biology, such as blood completely stopping but the person still walks, or the abdomen turning into a hollow cavity or a hive of insects throughout the entire body.

Illustrative clinical vignette

A patient says:

“I can clearly feel something big moving around in my belly, like a snake or a giant worm. It pushes my ribs out one by one. I feel it every day for months, but every time I get an ultrasound, the doctor says there’s nothing there. They don’t understand how much this torments me.”

2.3 Core of the Core Symptoms — How do we know this is “really a hallucination”?

To summarize the essential core in the article, these points form the heart of the core symptoms:

Abnormal perception in the “touch/body” modality

It is not just “thinking that you’re sick.”

It is the brain creating touch sensations / bodily sensations on its own, experienced by the person as if they are real.

No external stimulus as a clear cause

No insects, no one touching them, no wounds, no burns, no skin disease or organ disease that can explain it.

Or there may be minimal stimuli, but the perception is grossly exaggerated (for example, mild itching → interpreted as hundreds of insects under the skin).

Intensity and realism of the experience

Patients often say, in various words:

“It feels real, just like being really touched.”

When they describe it, they usually provide rich detail:

Where it moves from and to,

How heavy or light it feels,

Whether it is hot/cold, etc.

Insight level / awareness

Some still vaguely know:

“It probably isn’t real, but I can’t stop believing it.” (partial insight)

Another group believes it completely, leading to the formation of delusions to make sense of it, such as somatic delusions or persecutory delusions.

Emotional impact (distress)

Fear, anxiety, disgust, stress, insomnia, irritability.

For nihilistic-type somatic hallucinations, the person may drift into hopelessness, suicidal feelings, or believing they are already dead.

Impact on functioning (functional impairment)

Dropping out of work/school/relationships.

Going from hospital to hospital, wasting time and money.

Loss of self-esteem, feeling that they are “crazy / no one believes me.”

Risky behaviors

Scratching, gouging, cutting themselves to get rid of what they believe is there.

Refusing to take medication for the underlying disorder (e.g., antipsychotics) because they believe the problem is “in the body, not the brain.”

Risk of serious self-harm because they believe they are “already dead” or the body is “too rotten to save.”

3. Diagnostic Criteria — Structural Diagnostic Framework

This section explains to readers what clinicians look at when they conclude that something is tactile / somatic hallucination, and where it fits within DSM-5-TR / ICD-11.

3.1 Basic criteria for “Hallucination” under DSM-5-TR

DSM-5-TR does not create a separate diagnosis called “Tactile hallucinations disorder.”
Instead, it classifies tactile / somatic hallucinations as “forms of hallucination”, which then become symptoms within other disorders.

The main criteria for determining that “this is a hallucination” include:

It is a perception that occurs without an external stimulus.

For example, feeling insects crawling despite no insects, no rash, no visible signs.
Or feeling intestines twisting / bones breaking, even though tests / scans are normal.

The experience is vivid and lifelike.

It is not just daydreaming or vague fantasy.
The person reports that “it feels so real” that, at the time, they cannot distinguish it from genuine sensation.

It is not simply a normal sleep-related experience.

Hypnagogic/hypnopompic phenomena (hallucinations as one falls asleep or wakes up) can occur in healthy people.
Tactile/somatic hallucinations counted as pathological must occur primarily in the waking state.

It cannot be fully explained by cultural/religious norms.

For example, in certain possession rituals where people are “expected” to feel specific bodily sensations, those may be culturally sanctioned experiences.
Clinicians must determine whether the experience falls outside the typical cultural belief system.

When applied to tactile / somatic hallucinations, it can be summarized like this:

The patient reports feeling “touch, movement, or abnormalities in internal organs” with convincing realism, even though no external stimulus or physical pathology can be found to account for this, and these experiences cause significant distress or impairment in daily functioning.

3.2 Primary diagnoses where tactile / somatic hallucinations show up

In practice, clinicians do not write:

Diagnosis: Tactile hallucinations

but more like:

Schizophrenia, with tactile and somatic hallucinations

So, in your article, you can group them under “container diagnoses” like this:

3.2.1 Schizophrenia / Schizoaffective disorder / Delusional disorder

Tactile/somatic hallucinations can count toward Criterion A: Hallucinations.

They are often accompanied by:

Delusions (especially persecutory / somatic / nihilistic),
Disorganized speech,
Negative symptoms, etc.

Somatic hallucinations in this group tend to be very bizarre and extreme, e.g., feeling that the body is hollow, organs have been removed, etc.

3.2.2 Mood disorder with psychotic features

Examples: Major depressive disorder / Bipolar disorder with psychotic features

Tactile/somatic hallucinations often:

Are mood-congruent, for example:

In severe depression: feeling the body is rotting, being burned, or punished for sins → linked to feelings of worthlessness/guilt.
In mania: feeling the body is full of special power, electricity, or divine energy.

Diagnostic criteria examine whether the psychotic features (including hallucinations) occur only during mood episodes.

3.2.3 Substance-/Medication-Induced Psychotic Disorder

From substances or medications such as:

Stimulants: cocaine, methamphetamine, amphetamine.

Alcohol: especially during withdrawal.

Certain medications such as dopaminergic agents, anticholinergics, etc.

A classic tactile hallmark:

“Cocaine bugs” / “meth bugs” = intense formication + paranoia + severe insomnia.

The criteria state that:

Psychotic symptoms (including tactile/somatic hallucinations) begin during intoxication or withdrawal, and

Cannot be better explained by a pre-existing psychotic disorder.

3.2.4 Delirium / Dementia / Parkinson’s / Lewy body disease

In delirium:

Tactile/somatic hallucinations can occur alongside visual hallucinations, confusion, and fluctuating level of consciousness.

Key features: acute onset + fluctuating course + concurrent medical condition.

In Parkinson’s / Lewy body dementia:

Visual hallucinations often appear first, but tactile/somatic hallucinations can also occur.

May be associated with dopaminergic medications → diagnostic formulation considers whether the symptoms are medication-induced or due to the underlying disease.

3.2.5 Epilepsy / Brain lesions / Neurological disorders

Partial seizures (especially involving the parietal lobe / somatosensory cortex):

Tactile/somatic hallucinations of a localized area.
Short duration: seconds to minutes, often with stereotyped patterns.

Brain tumors / stroke / demyelinating diseases along somatosensory pathways:

Produce strange somatic sensations + objective neurological signs (weakness, numbness, clumsiness, etc.).

In such cases, the diagnosis is based on the primary neurological disorder, with hallucinations documented as one of the symptoms.

3.3 Diagnostic approach — Explained in simple terms

You can include this as a “framework” in your article to explain how clinicians think when they see tactile / somatic hallucinations:

Confirm that this is truly a hallucination, not something else

Differentiate from:

Illusions: there is a real stimulus but it is misinterpreted (for example, hair brushing the skin → interpreted as insects).

Physical paresthesia: from neuropathy, diabetes, B12 deficiency, nerve compression, etc.

Somatic delusions: fixed beliefs about the body without unusual sensations leading the way.

Take a detailed history + perform physical and neurological examination

To look for red flags:

Acute confusion, high fever, severe headache, unilateral weakness, slurred speech → think delirium / stroke / brain lesion.

Skin lesions → think of real dermatological disease before hallucination.

Connect the symptom to a “container diagnosis”

Is there a prior psychiatric history? (schizophrenia, bipolar, etc.)

What substances/medications are being used? (stimulants, alcohol, steroids, etc.)

Any neurological disorder / dementia / Parkinson’s / epilepsy?

Assess level of insight & coexisting delusions

If the person has strong accompanying beliefs (e.g., organs removed, devices implanted), this indicates a more severe level of psychosis.

Check if there is self-harm driven by the belief (e.g., cutting to remove “insects”).

Evaluate impact on life and risk

Sleep? Work? Relationships? Substance use?

Risk of harm to self/others? Risk of medication non-adherence or absconding from hospital?

Plan treatment

If it is an emergency (delirium, withdrawal, stroke, etc.) → acute medical management.

If it is psychotic disorder / mood disorder / substance-induced psychosis → plan psychiatric medication, address substances, and psychotherapy, etc.

3.4 How to summarize the diagnosis in an article (for general readers)

You can summarize it for lay readers like this:

Clinicians do not see tactile / somatic hallucinations as “standalone diseases.”

They see them as “signals” that the brain/mind or the body as a whole is in trouble.

In real diagnostic work, clinicians will:

Check whether it really is a hallucination.
Look for the main cause — psychiatric illness, neurological condition, substance use, or other physical disease.
Assess how much these experiences affect daily functioning and safety.

Then, treatment will:

Focus on the primary disorder, while also finding ways to help the patient cope better with the hallucinations.

4. Subtypes or Specifiers — Ways to Classify Subtypes

4.1 By modality: Tactile vs Somatic

Tactile hallucinations

Involve the skin / external points of contact.

Subtypes/examples:

Formication — feeling insects crawling on or under the skin (classic with cocaine / meth / alcohol withdrawal / menopausal states, etc.) Cleveland Clinic+2 Medical News Today+2

Sensations like electric shocks, needle pricks, burning, etc.

Somatic hallucinations (including cenesthetic) Wikipedia+2 Healthline+2

General somatic hallucinations

Feeling the body being twisted, bent, torn, or containing animals inside internal organs.

Algesic hallucinations

Hallucinations of pain — bizarre pain with no pathology to explain it (must be carefully distinguished from genuine chronic pain).

Kinesthetic hallucinations

Feeling limbs or the body moving when they are actually still.

Cenesthopathic (cenesthetic) hallucinations

Deep, strange bodily sensations in visceral organs, e.g., boiling blood, burning brain, rotting intestines, etc.

4.2 By cause/context

Psychotic-spectrum — schizophrenia / schizoaffective / delusional disorder

Mood-related — bipolar / major depression with psychotic features

Substance-induced — stimulants, alcohol withdrawal, hallucinogens, some synthetic drugs, some medications (such as dopaminergic agents in Parkinson’s) American Addiction Centers+3 Rama Mahidol University+3 Medical News Today+3

Neurological / Medical — epilepsy, brain tumor, stroke, certain neuropathies, endocrine/metabolic (such as B12 deficiency, thyroid problems)

Sleep-related / deprivation — severe sleep deprivation can trigger hallucinations, including tactile/somatic, even in people without prior psychosis.

4.3 By emotional tone

Ego-dystonic / distressing — being harmed, burned, invaded by animals, etc. → often tied to persecutory / somatic delusions.

Ego-syntonic / neutral / pleasant — feeling hugged, stroked, sexually touched in a pleasurable way (seen in some cases, but one must be cautious about possible underlying trauma or dissociation) Healthline+1.

5. Brain & Neurobiology — Neural Mechanisms Involved

In brief:
Tactile / somatic hallucinations do not arise from “pure imagination,” but from disrupted sensory and body-perception processing in the brain, plus a distorted “world-prediction system” (predictive coding). The brain then “creates touch/bodily sensations from within” and believes they are real.

5.1 Somatosensory & interoceptive networks involved

There are four major zones:

Primary somatosensory cortex (S1) – located at the postcentral gyrus

Receives basic tactile input from the skin (touch, pressure, vibration, pain, temperature).
Has a somatotopic map, where each body part occupies its own cortical area.
If S1 is hyperactive or fires spontaneously without input → it can generate illusory touch sensations.

Secondary somatosensory cortex (S2) & Posterior parietal cortex

S2 integrates inputs from multiple S1 regions.
The posterior parietal cortex integrates touch + visual + proprioceptive input to construct a body schema (internal representation of the body).
If this network is disrupted → the sense of “where the body is / what state it’s in” becomes distorted → making it easier for somatic/cenesthetic hallucinations to arise. ScienceDirect+2 Wiley Online Library+2

Insula (insular cortex)

The central hub of interoception — perception of internal bodily states (heartbeat, gut motility, fullness, hunger, etc.).
Strongly connected with the limbic system (emotion) → internal sensations and emotions are tightly linked, e.g., chest tightness = anxiety.
Several studies on visceral / cenesthetic hallucinations point to insula and interoceptive networks being dysfunctional in certain somatic hallucination cases. Wiley Online Library+1

Thalamus & brainstem sensory pathways

The thalamus is the “relay station” for most sensory signals.
If thalamic transmission is abnormal (overactive / misrouted) → minor sensory signals can be amplified or spontaneous firing can occur without input.
Some epilepsy / lesion cases involving the thalamus or somatosensory pathways report localized somatic/tactile hallucinations. ScienceDirect+1

Overall picture:

Tactile hallucinations → emphasize S1/S2 + parietal.

Somatic/cenesthetic hallucinations → emphasize insula + parietal + thalamus + limbic network.

All of these sit atop large-scale salience / default mode / attention networks, which determine how important a given sensation feels.

5.2 Predictive coding model — When the brain “mis-predicts” and hallucinates

The predictive coding model has almost become the main framework for explaining hallucinations in psychosis. Frontiers+3 PMC+3 pure.ed.ac.uk+3

Basic idea:

The brain doesn’t merely wait for data from the world.

It predicts what it expects to see/hear/feel (prediction, prior) first.

Then it compares the real sensory input to its prediction → producing a prediction error.

If the prediction is wrong → the brain updates its predictions or beliefs.

If the system is dysregulated, for example:

The brain gives too much weight to top-down predictions, or

Too little / noisy weight to bottom-up sensory input,

then the brain may trust its prediction more than reality → resulting in perception without a real stimulus = hallucination.

Applied to tactile/somatic hallucinations:

People who have had intense prior experiences involving the body/touch (severe illness, physical assault, sexual abuse, etc.), or who have strong bodily preoccupation (somatic delusions, health anxiety),

May end up with a “body model” saturated with threat — they pre-emptively expect that:

“There’s probably something wrong with my body all the time.”

Minor bodily signals such as:

Pulse/vascular pulsations under the skin,
Small muscle twitches,
Normal bowel movements (peristalsis),
Clothing lightly rubbing the skin,

are then interpreted as evidence supporting the pre-existing prediction, such as:

“There are insects under my skin,” or
“My intestines are twisting because they are rotten.”

fMRI and EEG studies in schizophrenia show that:

People with hallucinations have abnormal prediction-error processing in sensory cortex and frontal–temporal–parietal networks. Frontiers+4 PMC+4 pure.ed.ac.uk+4

Connectivity between sensory cortex and frontal control networks is altered → they cannot effectively filter out noise.

Extrapolating to tactile/somatic hallucinations suggests a similar mechanism, but in somatosensory + interoceptive networks rather than auditory/visual systems.

In lay terms:

If the brain’s prediction is “There must be something wrong with my body,” and it gives that thought very high credibility, then even minimal or absent bodily signals can be “filled in” by the brain as fully formed sensations. That’s how tactile / somatic hallucinations can feel so vividly real.

5.3 Neurotransmitter systems involved

5.3.1 Dopamine

In psychosis in general (especially schizophrenia spectrum), there is strong evidence that dopamine in the mesolimbic system is elevated.

The “aberrant salience” theory says dopamine tags stimuli with importance. If dopamine firing is out of sync, the system:

Attaches high salience to stimuli that ordinarily shouldn’t matter (e.g., mild itch, slightly increased heart rate).
The brain then concludes, “This is a big deal,” which leads to increasingly bizarre beliefs and misinterpretations. PMC+2 pure.ed.ac.uk+2

Real-world example:

Parkinson’s disease

Patients have low dopamine → treated with dopaminergic therapy (L-Dopa, dopamine agonists).
Increasing dopamine improves motor symptoms but, in some patients, causes hallucinations (including tactile/somatic) and delusions, especially at higher doses or in older adults. NUPLAZID® (pimavanserin) Patient Website+4 jneuropsychiatry.org+4 PubMed+4
Case reports of tactile / cenesthetic hallucinations in Parkinson’s linked to dopaminergic medications continue to appear. jnnp.bmj.com+1

Delusional infestation / formication from drugs

Cocaine, amphetamine, and some drugs that block the dopamine transporter → increase synaptic dopamine → resulting in tactile hallucinations like “bugs under the skin” or formication; in some cases evolving into full-blown delusional parasitosis. Archstone Behavioral Health+4 PMC+4 ScienceDirect+4

5.3.2 Glutamate / GABA

The predictive coding framework is tied to the excitatory–inhibitory balance:

Glutamate (excitatory)
GABA (inhibitory)

If inhibitory control is weak → sensory cortex becomes hyperexcitable, prone to spontaneous firing without real input.

In schizophrenia, evidence of NMDA receptor hypofunction (glutamate) suggests predictive coding disruptions across the brain, including somatosensory cortex. pure.ed.ac.uk+2 ScienceDirect+2

5.3.3 Serotonin and other systems

In Parkinson’s psychosis, pimavanserin (a 5-HT2A inverse agonist) is used to treat hallucinations without suppressing dopamine, indicating serotonin’s important role in hallucination generation. Parkinson's Foundation+1

Classic hallucinogens such as LSD and psilocybin act mainly via 5-HT2A receptors, reshaping perception and predictive coding.

Other systems — acetylcholine (crucial in delirium), noradrenaline (arousal, stress) — also influence how bodily signals are interpreted.

5.4 Sense of agency, body ownership, and self-monitoring

Another important piece is the sense of body ownership and sense of agency (the sense that “I am the one who is acting/feeling this”), which are clearly disrupted in schizophrenia. OUP Academic+1

If self-monitoring is impaired:

The brain cannot properly distinguish between “signals generated by me” versus “forces or entities acting on me from outside.”

In some tactile/somatic hallucination cases, patients feel that:

The sensations come from other people / other beings / supernatural forces.

Their own organs are being controlled / modified / altered by external forces (e.g., jinn, ghosts, gods, secret organizations, etc.).

Research among Muslim patients with psychosis has found that tactile/somatic hallucinations are often interpreted as attacks by jinn or supernatural entities, linking together body schema, self–other boundaries, and cultural belief systems. Frontiers

5.5 Why do some people “hallucinate through the body” more than others?

Currently, some plausible factors include:

Each person has a dominant “channel”

Some hallucinate mainly through audition (hearing voices).
Some through vision.
Some very strongly through tactile/somatic channels → often linked to personality and life history (e.g., health preoccupation/hypochondriasis, frequent illness, past bodily trauma, etc.). Frontiers+3 PMC+3 Wikipedia+3

Particularly sensitive brain networks

If a person already has epilepsy / lesions / neuropathy / chronic pain, the body and somatosensory networks may be hyperplastic (more easily altered).
When predictive coding destabilizes, the tactile/somatic channel becomes the easiest route for hallucinations.

Past experiences and meanings attached to the body

People who have experienced repeated physical or sexual abuse → traumatic memories may be encoded more as “body memories” rather than as images or words.
When these memories re-emerge (re-experiencing), they can resemble sexualized tactile hallucinations. PsychDB+1

6. Causes & Risk Factors — Causes and Risk Modifiers

Big picture: there is no single cause that explains tactile/somatic hallucinations in all cases. They are usually the combined result of multiple layers:

Brain/neurotransmitter abnormalities

Psychiatric / neurological / physical illnesses

Substances/medications

Life experiences, culture, and personality

You can present these as layers:

6.1 Psychiatric causes

6.1.1 Schizophrenia spectrum disorders

Tactile/somatic hallucinations occur less frequently than auditory ones, but when present, they often tie strongly to persecutory or somatic/nihilistic delusions. PMC+2 Wikipedia+2

Examples of themes:

Being used in medical experiments

Having organs removed

Having listening devices implanted in bones

Blood has stopped flowing, organs are rotten, but the world refuses to acknowledge it

Condition:

There must be other psychotic symptoms as well, such as delusions, disorganized thought, negative symptoms, etc.

6.1.2 Mood disorders with psychotic features

Major depressive disorder with psychotic features

Somatic hallucinations often involve punishment / bodily destruction.
For example: feeling the body is burning from within, the liver is rotten, the blood has turned to sludge.

Bipolar disorder with psychotic features

In mania, somatic hallucinations may be grandiose, e.g., feeling the body is filled with special powers, electricity, or divine energy.

6.1.3 PTSD / Dissociation / Trauma-related conditions

People who have been repeatedly sexually/physically abused → trauma is often encoded at the bodily level.

Triggers can cause these sensations to return in an extremely vivid way, making them hard to distinguish from tactile hallucinations.

There are reports of sexualized/violative tactile hallucinations in this group, although systematic evidence is not as robust as in schizophrenia. PsychDB+1

6.2 Neurological & general medical causes

6.2.1 Epilepsy (especially frontal / parietal lobe)

Partial seizures involving the somatosensory cortex can cause localized tactile or somatic hallucinations.

Characteristic features:

Short duration (seconds–minutes).

Repetitive, stereotyped patterns.

May have accompanying motor signs or impaired awareness.

There are also reports of somatic/cenesthetic hallucinations following nonconvulsive status epilepticus in the frontal lobe. ScienceDirect+1

6.2.2 Brain tumor / stroke / lesions

Lesions in the somatosensory cortex, parietal lobe, thalamus, or related pathways can distort sensory signals, producing odd bodily sensations that patients may describe as hallucinations.

These must be distinguished from ordinary paresthesias, but in general, if there are focal neurological signs (weakness, numbness on one side, etc.), lesion-based causes must be considered before psychosis.

6.2.3 Neurodegenerative diseases

Parkinson’s disease, Lewy body dementia, some cases of Alzheimer’s

Hallucinations (with visual ones most prominent), but tactile/somatic hallucinations are also reported.
Mixed factors:

Neurodegeneration in brainstem/cortex.
Use of dopaminergic/anticholinergic medications.

In PD, there are cases of tactile / cenesthetic hallucinations involving perceived changes in internal organs or strange sensations during treatment with dopamine agonists. NUPLAZID® (pimavanserin) Patient Website+5 jneuropsychiatry.org+5 jnnp.bmj.com+5

6.2.4 Peripheral neuropathy / chronic pain

Damaged nerves (diabetic neuropathy, B12 deficiency, toxic neuropathies, etc.) send abnormal signals to the brain → numbness, burning, unusual pain.

In some patients, especially those with anxiety/psychosis, this can evolve into a narrative that “something is inside the body” or “the body is being attacked from within.”

This is not pure hallucination, but a mix of physical nerve problems + psychotic interpretation.

6.2.5 Metabolic / endocrine / delirium

Conditions such as sepsis, organ failure, electrolyte imbalance, hypoglycemia, thyroid disorders, B12 deficiency, hepatic encephalopathy can lead to delirium.

In delirium, there may be visual, tactile, somatic hallucinations plus disorientation in time/place/person.

If an elderly, severely ill patient suddenly reports insects crawling on the body or things inside the abdomen, along with marked confusion → delirium should be considered first, not a primary psychiatric illness. PMC+1

6.3 Substance- & medication-related causes

This group is crucial, as tactile/somatic hallucinations are highly visible in the context of drugs and alcohol.

6.3.1 Stimulants (cocaine, methamphetamine, amphetamine, etc.)

“Cocaine bugs / meth bugs” are classic examples of formication.

Mechanisms in broad strokes:

Increased dopamine and noradrenaline → increased nerve activity and overactive sensory systems.

This leads to sensations of insects crawling on or under the skin, even when nothing is there. Wikipedia+5 PMC+5 ScienceDirect+5

Often accompanied by:

Severe insomnia, appetite loss, paranoia, and aggressive behavior.

This is often the starting point where a tactile hallucination progresses into delusional infestation (100% conviction of having insects inside the body). Psychiatrist.com

6.3.2 Alcohol withdrawal / Alcohol-induced psychosis

In alcohol withdrawal, especially delirium tremens:

Tactile hallucinations in the form of formication are common: feeling insects or small animals crawling on or inside the body.
Typically accompanied by visual hallucinations, tremors, sweating, high blood pressure, and confusion.

In this context, it is considered a medical emergency requiring hospital care, not simply “depression/psychosis management.” Magnified Health Systems+3 ScienceDirect+3 Wikipedia+3

6.3.3 Medications

Many drug classes have been linked to tactile/somatic hallucinations:

Dopaminergic agents – levodopa, dopamine agonists in Parkinson’s:

Increase dopamine → increase risk of psychosis and hallucinations of all types, including tactile/somatic and cenesthetic. Parkinson's Foundation+3 jns-journal.com+3 Wiley Online Library+3

Anticholinergics – some antiparkinsonian drugs, some antihistamines:

Can cause confusion, delirium, and hallucinations, especially in older adults. Magnified Health Systems+1

Opioids, steroids, certain pain medications, some hypnotics:

There are case reports of hallucinations, including tactile/somatic, in some individuals, especially at high doses or in combination with pre-existing brain disorders. PMC+1

6.4 Lifestyle / psychosocial & cultural factors

These are not direct causes, but risk modifiers that increase the likelihood of tactile/somatic hallucinations in vulnerable individuals.

Severe sleep deprivation

Staying awake for many nights can push the brain into a quasi-delirious state — visual, auditory, and tactile/somatic hallucinations can occur even in people with no prior psychiatric diagnosis. PMC+1

Chronic stress / trauma

Individuals in prolonged high-stress situations (threat, confinement, ongoing violence, etc.) are at increased risk of developing psychosis and dissociation.
The brain may encode threat through bodily channels more strongly.

Culture and belief systems

In some cultures, tactile/somatic hallucinations are interpreted as “ghosts, curses, jinn, sleep paralysis entities, spirits touching the body”.
This can lead patients to not see themselves as ill, but to attribute it to supernatural causes → delay in seeking medical help and increased risk of self-harm when trying to “remove the bad thing.” Frontiers+1

Personality and interoceptive sensitivity

People who are highly sensitive to bodily sensations (panic-prone, health-anxious) plus fragile neurobiology → when predictive coding destabilizes, they are more likely to manifest somatic/tactile hallucinations than those who are less body-focused.

6.5 Multi-layer model summary

To give readers a simple model:

Bottom layer (Neurobiology)

Abnormal somatosensory/interoceptive networks + dopamine/glutamate/GABA imbalances + faulty predictive coding → the brain is primed to “generate hallucinatory sensations.”

Middle layer (Core disorders)

Schizophrenia / mood psychosis / epilepsy / Parkinson’s / delirium / substance-induced psychosis, etc. → act as diagnostic frameworks sustaining these abnormalities.

Top layer (Real life & culture)

Trauma, substance use, sleep deprivation, stress, cultural beliefs about spirits/curses, etc. → guide which “story” the brain picks to explain those strange sensations.

This yields highly diverse tactile / somatic hallucination content:

Some describe it as “insects crawling.”

Some as “rotting organs.”

Some as “special powers inside the body.”

Some as “ghosts / jinn / deities / secret organizations” doing something to their body.

But the common core is:

The brain is generating touch/body sensations on its own that do not match what is actually happening in the body at that moment.

7. Treatment & Management — Approaches to Treatment and Care

Mindset summary:
Treat the “cause” + manage the “hallucinatory experience”.

7.1 First step: Assessment

Detailed history

Nature of the sensations, location, duration, triggers, associated beliefs.
Substance/alcohol/medication history, medical conditions, trauma history, prior psychiatric diagnoses.

Physical and neurological examination

To rule out dermatologic disease, neuropathy, infections, delirium, stroke, etc.

Identify emergencies

Acute confusion, high fever, abnormal BP/HR, risk of self-harm/violence → immediate referral to ER is required.

7.2 Pharmacological treatment (depends on primary disorder)

Antipsychotics

For schizophrenia spectrum / mood disorders with psychotic features / significant substance-induced psychosis.
Examples: risperidone, olanzapine, quetiapine, haloperidol, etc. (actual choices depend on the individual case and physician judgment).

Benzodiazepines / anxiolytics

Short-term use in alcohol withdrawal or severe agitation, under close medical supervision. Nova Recovery Center Near Austin Texas+1

Neuropathic pain agents

Such as gabapentin, pregabalin, certain TCAs, in cases with real neuropathy or pain components.

Adjusting causative medications

Reducing or changing dopaminergic agents in Parkinson’s when hallucinations are severe (balancing against motor symptoms). Healthline+1

Note: Dosages and regimens must always be determined by a qualified physician.

7.3 Psychosocial & psychological interventions

Psychoeducation

Explaining that tactile/somatic hallucinations are symptoms of nervous system/mental health issues, not “craziness” or “being cursed.”

CBT for psychosis (CBTp)
Helps patients:

Distinguish “the hallucinatory experience” from “the interpretation of it.”
Reduce fixed beliefs such as “there really are insects inside me.”

Grounding & coping skills for hallucinations

Techniques to shift attention, focusing on real external stimuli (e.g., feeling a real object in hand).
Slow breathing, relaxation, mindfulness to reduce panic.

Supportive therapy / family psychoeducation

Helping families understand the symptoms, avoid simply arguing “it’s not real,” and instead focus on the person’s distress and safety.

7.4 Behavioral and environmental adjustments

Safely reducing or quitting substances and alcohol (often requiring detox or rehab programs in many cases). Nova Recovery Center Near Austin Texas+1

Establishing good sleep hygiene, reducing stress, maintaining a consistent daily routine.

If the patient scratches or injures themselves due to formication:

Proper skin care, infection prevention, and behavioral strategies to redirect self-harming actions.

8. Notes — Cautions / Additional Explanations

Clearly distinguish from “somatic delusions.”

Somatic hallucination = a felt bodily sensation (e.g., feeling worms in the stomach).
Somatic delusion = a belief about the body (e.g., believing the liver is gone) even without unusual sensations.

In clinical practice, these often come together (a strange sensation → a delusional explanation), but in taxonomy it is useful to explain to readers that they are different constructs. Wikipedia+1

Not every case of “itching / burning” is hallucination.

Dermatologic conditions, allergies, neuropathies, and medication side effects must be ruled out first.

In ER settings, think delirium, alcohol withdrawal, drug intoxication first.

Why are tactile/somatic hallucinations mentioned less often than auditory/visual?

Patients often find them very hard to describe, and many feel ashamed to talk about them (especially when sexual or involving genitals/anus).
This likely leads to underestimation of their prevalence in many studies. Psychology Today+1

Cultural aspects

In some cultures, tactile/somatic hallucinations are viewed as magic, curses, possession, ghosts, etc.
This can delay medical care and increase the risk of self-injury when attempting to remove “evil objects” or “bad spirits.”

When to seek emergency care

When hallucinations are accompanied by severe confusion, recent cessation of alcohol/drugs, high fever, severe headache, unilateral weakness, slurred speech,
Or when suicidal/homicidal thoughts emerge — immediate emergency medical evaluation is needed.

Read Schizophrenia

References

Rajender, G., et al. (2009). Study of cenesthesias and body image aberration in schizophrenia. Indian Journal of Psychological Medicine, 31(2), 71–76. PMC
Juan, C. J., et al. (2018). Prickling or Formication after the Use of Cocaine. Case report in Revista de Psiquiatría y Salud Mental / PubMed Central. PMC
Cleveland Clinic. (2022). Tactile Hallucinations (Formication): Causes & Treatment. Cleveland Clinic
Roncero, C., et al. (2017). Higher severity of cocaine addiction is associated with tactile/somatic hallucinations (CITSH). European Psychiatry. ScienceDirect
Horga, G., Schatz, K. C., Abi-Dargham, A., & Peterson, B. S. (2014). Deficits in Predictive Coding Underlie Hallucinations in Schizophrenia. Journal of Neuroscience, 34(24), 8072–8082. PubMed+2 jneurosci.org+2
Qela, B., et al. (2025). Predictive coding in neuropsychiatric disorders: a systematic review. Neuroscience & Biobehavioral Reviews. ScienceDirect
Jenkins, G., & Röhricht, F. (2015). From Cenesthesias to Cenesthopathic Schizophrenia: Theoretical and Clinical Perspectives. In: From Cenesthesias to Cenesthopathic Schizophrenia. Semantic Scholar
Nakano, H., et al. / Kataoka, H. (2014). Can dopamine agonists trigger tactile hallucinations in patients with Parkinson’s disease? Journal of the Neurological Sciences. ScienceDirect
Weil, R. S., et al. (2020). Hallucinations in Parkinson's disease: new insights into mechanisms and treatments. Movement Disorders / PMC. PMC
Abdul-Rahman, T., et al. (2024). Management of psychosis and hallucinations in Parkinson’s disease: a focus on pimavanserin, quetiapine and clozapine. Journal of Integrative Neuroscience. IMR Press
Kemperman, P. M. J. H., et al. (2022). Drug-induced Delusional Infestation. CNS Drugs. PMC
Kansal, N. K., et al. (2025). Delusional infestation: An update. Cosmoderma. Cosmoderma
Mindru, F. M., et al. (2024). Insights into the Medical Evaluation of Ekbom Syndrome (Delusional Infestation). International Journal of Molecular Sciences. MDPI
Murugan, K., et al. (2024). Signs and terminologies in cutaneous manifestations of substance abuse. Indian Journal of Dermatology, Venereology and Leprology. (Includes a section explaining formication as a tactile hallucination.) Indian J Dermatology
Karger Publishers. (2018). Cenesthopathy and Subjective Cognitive Complaints in Schizophrenia. Psychopathology. Karger Publishers
Article: Hallucinations of Bodily Sensation. (A review of tactile / somatic / cenesthetic hallucinations and body schema in psychosis.) ResearchGate

You can also include a standard diagnostic reference:

American Psychiatric Association. Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition, Text Revision (DSM-5-TR). APA Publishing.

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