Tangential speech or tangentiality is a communication disorder in which the train of thought of the speaker wanders and shows a lack of focus, never returning to the initial topic of the conversation. It tends to occur in situations where a person is experiencing high anxiety, as a manifestation of the psychosis known as schizophrenia, in dementia or in states of delirium. It is less severe than logorrhea and may be associated with the middle stage in dementia. It is, however, more severe than circumstantial speech in which the speaker wanders, but eventually returns to the topic.
Some adults with right hemisphere brain damage may exhibit behavior that includes tangential speech. Those who exhibit these behaviors may also have related symptoms such as seemingly inappropriate or self-centered social responses, and a deterioration in pragmatic abilities (including appropriate eye contact as well as topic maintenance).
The term refers simplistically to a thought disorder shown from speech with a lack of observance to the main subject of discourse, such that a person whilst speaking on a topic deviates from the topic. Further definition is of speech that deviates from an answer to a question that is relevant in the first instance but deviates from the relevancy to related subjects not involved in a direct answering of the question. In the context of a conversation or discussion the communication is a response that is ineffective in that the form is inappropriate for adequate understanding. The person's speech seems to indicate that their attention to their own speech has perhaps in some way been overcome during the occurrence of cognition whilst speaking, causing the vocalized content to follow thought that is apparently without reference to the original idea or question; or the person's speech is considered evasive in that the person has decided to provide an answer to a question that is an avoidance of a direct answer.
The earlier phenomenological description (Schneider 1930;et al.) allowed for further definition on the basis of formal characteristic rather than content, producing later practice relying upon clinical assessment (Andreasen 1979). The term has undergone a re-definition to refer only to a persons speech in response to a question, and to provide the definition separation from the similar symptoms loosening of association and derailment (Andreasen 1979).
- Forensic Aspects of Communication Sciences and Disorders by Dennis C. Tanner 2003 ISBN 1-930056-31-1 page 289
- G. David Elkin (1999). Introduction to clinical psychiatry. McGraw-Hill Professional - 1999. ISBN 9780838543337. Retrieved 2012-01-17.
- Crash Course: Psychiatry by Julius Bourke, Matthew Castle, Alasdair D. Cameron 2008 ISBN 0-7234-3476-X page 255
- Introduction to Neurogenic Communication Disorders by Robert H. Brookshire 1997 ISBN 0-323-04531-6 page 393
- Perspectives on Treatment for Communication Deficits Associated With Right Hemisphere Brain Damage by Margaret Lehman Blake 2007 ISSN 1058-0360 page 333
- P. J. McKenna, Tomasina M. Oh Schizophrenic speech: making sense of bathroots and ponds that fall in doorways - 210 pages. Cambridge University Press, 2005. 2005-02-17. ISBN 9780521810753. Retrieved 2012-01-12. ISBN 0-521-81075-2
- Tali Ditman & Gina R. Kuperberg Building coherence : A framework for exploring the breakdown of links across clause boundaries in schizophrenia. Martinos Center for Biomedical Imaging. Retrieved 2012-01-17.
- Howard H. Goldman 2000 - Review of general psychiatry - 583 pages A Lange medical book McGraw-Hill Professional, Retrieved 2012-01-17 ISBN 0-8385-8434-9
- Jeffrey A. Lieberman, T. Scott Stroup, M.D., Diana O. Perkins, M.D. 2011 Essentials of Schizophrenia - 268 pages American Psychiatric Pub, 2 Jun 2011 Retrieved 2012-01-12 ISBN 1-58562-401-2
- S.J.Wood, N.B.Allen & C.Pantelis (Editors) 2009 - The Neuropsychology of Mental Illness Cambridge University Press Archived 2016-03-04 at the Wayback Machine Retrieved 2012-01-17 ISBN 978-0-521-86289-9
- Branca Telles Ribeiro 23 Jun 1994 - Coherence in psychotic discourse - 320 pages Oxford studies in sociolinguistics Oxford University Press, Retrieved 2012-01-17 ISBN 0-19-506615-4
- Stephens, J. H.; Astrup, C.; Carpenter Jr, W. T.; Shaffer, J. W.; Goldberg, J. (1982). "A comparison of nine systems to diagnose schizophrenia". Psychiatry Research. 6 (2): 127–43. doi:10.1016/0165-1781(82)90001-4. PMID 6953455.
- Urfer Parnas, A.; Jansson, L.; Handest, P.; Nielsen, J.; Sæbye, D.; Parnas, J. (2007). "Premorbid IQ varies across different definitions of schizophrenia". World Psychiatry. 6 (1): 38–41. PMC 1805734. PMID 17342225.