What are cenesthetic (or coenesthetic) hallucinations and what causes them?

Answer: A cenesthetic hallucination is the false sensation of an internal organ.

Hallucinations, broadly speaking, are false sensations or perceptions. When people think of hallucinations, they commonly think about auditory hallucinations, such as when a patient hears voices in their head, or visual hallucinations, such as seeing things that aren’t there. Charles Bonnet syndrome, which may happen when a person completely loses their vision and afterwards begins to see vivid imagery, is an example of a visual hallucination disorder.

A less well-known category of hallucinations are somatic hallucinations. These are false sensations or perceptions on your skin, for example, which are called tactile hallucinations. Tactile hallucinations can also affect the joints and muscles. They may feel like something is touching or different temperatures. Sometimes these sensations are also called tactile delusion. Odds are you may have experienced a common somatic hallucination: the phantom phone vibrating in your pocket. 

A different form of a somatic delusion is when we experience some kind of sensation of the internal organs, called visceral hallucinations. These are classified as cenesthetic hallucinations, or cenestopathy. Some sensations reported that qualify as a cenesthetic hallucination include the feeling that the internal organs have shifted around, that there are temperature waves flowing through the internal organs, that the mouth has been coated in slime (called oral cenesthetic hallucinations) or that a part of the body may feel hollow.

What causes cenesthetic hallucinations?

The exact cause of these phantom experiences is unknown. But, some case studies and retrospective studies have provided clues as to what might cause the sensation.

Schizophrenia. Schizophrenia is a mental disorder that affects around 1% of people. It is best known for producing auditory hallucinations and delusional thought, but can also produce cenesthetic hallucinations. In a small study, it was found that upwards of 80% of people with schizophrenia reported some degree of cenestopathy. Some of these patients reported that their body was distorted in size. Since the dopaminergic system is implicated in schizophrenia, there is a suggestion that dopamine dysregulation may be a contributing factor to cenesthetic hallucinations. However, cenesthetic schizophrenia has not been defined as a form of schizophrenia under the Diagnostic and Statistical Manual for Mental Diseases.  

Treatment of Parkinson’s disease with dopaminergic modifying drugs. One of the most common and effective treatments for the motor symptoms of Parkinson’s disease is a levodopa / carbidopa mix. In one case study, a woman reported that she felt as if her bowels had started to extrude from her arms. She felt these sensations so severely that she scratched her arms until lesions formed. Her medical team treated her with a drug called clozapine, which is commonly prescribed as an antipsychotic used for decreasing symptoms of schizophrenia. Clozapine's main mechanism of action is to interact with the serotonin and dopamine systems. 

Stroke recovery. In a rare case study of a stroke survivor, a woman reported the feeling of a metal object in her mouth, characteristics of an oral cenesthetic delusion. Using a real time imaging technique called magnetoencephalography, the researchers believe there was some cortical remapping or restructuring after the stroke that led to expansion of the primary somatosensory cortex. This type of plasticity is seen after many different forms of brain damage. 

How are cenesthestic hallucinations treated?

Generally, cenesthetic delusions are best treated by addressing the underlying cause. Most commonly, this is treating the schizophrenia, which produces both delusional thinking and hallucinations. Schizophrenia symptoms may be treated with some dopaminergic drugs. Drugs used for treating psychosis are often helpful for people with schizophrenia, such as haloperidol (Haldol).

Antidepressants may also have a benefit for these hallucinations. 

Outside of pharmacology, electroconvulsive therapy (ECT) and psychotherapy have been used, with varying results.