Also known as somatosensory hallucination. Both terms are indebted to the Greek noun soma, which means body. They are used to denote a hallucination that mimics feelings from inside the body, such as sensations in the belly or the limbs. Conceptually as well as clinically, somatic hallucinations are difficult to distinguish from *tactile hallucinations, bodily feelings arising from somatic conditions, somatic delusions, and *body schema illusions. A noteworthy example in this respect is inexplicable pain: a textbook example of a feeling that cannot be explained away by calling it a hallucination. Functional magnetic resonance imaging (fMRI) studies indicate that somatic hallucinations are associated primarily with heightened activity in the primary somatosensory cortex, the posterior parietal cortex, and the thalamus. During the era of classic psychiatry, some of the phenomena now referred to as somatic hallucinations were known as * coenesthetic hallucinations or * distortions of vital sensations. Another related notion is the * somaesthetic hallucination. The differential diagnosis of somatic hallucinations includes *haptic hallucinations, *body schema illusions, * paraesthesia, * alloesthaesia, * allodynia, *hyperalgesia, * hyperpathia, * hallucinated pain, referred pain, and pain due to an unknown somatic condition. The term somatic hallucination is used in opposition to the term *tactile hallucination (or haptic hallucination). Together, somatic and tactile hallucinations are referred to in the 1982 Manual for the Assessment and Documentation of Psychopathology (AMDP) as *bodily hallucinations.
References
Berrios, G.E. (1985). Hallucinosis.In: Neu-robehavioural disorders. Edited by Frederiks, J.A.M. Amsterdam: Elsevier Science Publications.
Guy, W., Ban, T.A., eds. (1982). The AMDP-system: Manual for the assessment and documentation of Psychopathology. Berlin: Springer.
Shergill, S.S., Cameron, L.A., Brammer, M.J., Williams, S.C., Murray, R.M., McGuire, P.K. (2001). Modality specific correlates of auditory and somatic hallucinations. Journal of Neurology, Neurosurgery and Psychiatry, 71, 688-690.
Dictionary of Hallucinations. J.D. Blom. 2010.