Geschwind syndrome, also known as Gastaut-Geschwind, is a group of behavioral phenomena evident in some people with temporal lobe epilepsy. It is named for one of the first individuals to categorize the symptoms, Norman Geschwind, who published prolifically on the topic from 1973 to 1984. There is controversy surrounding whether it is a true neuropsychiatric disorder. Temporal lobe epilepsy causes chronic, mild, interictal (i.e. between seizures) changes in personality, which slowly intensify over time. Geschwind syndrome includes five primary changes; hypergraphia, hyperreligiosity, atypical (usually reduced) sexuality, circumstantiality, and intensified mental life. Not all symptoms must be present for a diagnosis. Only some people with epilepsy or temporal lobe epilepsy show features of Geschwind syndrome.
Hypergraphia is the tendency for extensive and compulsive writing or drawing, and has been observed in persons with temporal lobe epilepsy who have experienced multiple seizures. Those with hypergraphia display extreme attention to detail in their writing. Some such patients keep diaries recording meticulous details about their everyday lives. In certain cases, these writings demonstrate extreme interest in religious topics. Also, these individuals tend to have poor penmanship. The novelist Fyodor Dostoyevsky showed symptoms of Geschwind syndrome, including hypergraphia. In some cases hypergraphia can manifest with compulsive drawing. Drawings by patients with hypergraphia exhibit repetition and a high level of detail, sometimes morphing writing with drawing 
Some individuals may exhibit hyperreligiosity, characterized by increased, usually intense, religious feelings and philosophical interests, and partial (temporal lobe) epilepsy patients with frequent numinous-like auras have greater ictal and interictal spirituality. Some auras include ecstatic experiences. It has been reported that many religious leaders exhibit this form of epilepsy. These religious feelings can motivate beliefs within any religion, including Voodoo, Christianity, Islam, and others. Furthermore, in Geschwind syndrome, "in someone from a strongly religious background hyperreligiosity might appear as deeply felt atheism". There are reports of patients converting between religions. A few patients internalize their religious feelings: when asked if they are religious they say they are not. One reviewer concluded that the evidence for a link between temporal lobe epilepsy and hyperreligiosity "isn't terribly compelling".
People with Geschwind syndrome reported higher rates of atypical or altered sexuality. In approximately half of affected individuals hyposexuality is reported. Less commonly, cases of hypersexuality have been reported.
Individuals that demonstrate circumstantiality (or viscosity) tend to continue conversations for a long time and talk receptively.
- Devinsky, J.; Schachter, S. (2009). "Norman Geschwind's contribution to the understanding of behavioral changes in temporal lobe epilepsy: The February 1974 lecture". Epilepsy & Behavior. 15 (4): 417–24. doi:10.1016/j.yebeh.2009.06.006. PMID 19640791.
- Benson, D. F. (1991). "The Geschwind syndrome". Advances in Neurology. 55: 411–21. PMID 2003418.
- Tebartz Van Elst, L.; Krishnamoorthy, E. S.; Bäumer, D.; Selai, C.; von Gunten, A.; Gene-Cos, N.; Ebert, D.; Trimble, M. R. (2003). "Psychopathological profile in patients with severe bilateral hippocampal atrophy and temporal lobe epilepsy: Evidence in support of the Geschwind syndrome?". Epilepsy & Behavior. 4 (3): 291–297. doi:10.1016/S1525-5050(03)00084-2. PMID 12791331.
- Benson, D.F. & Hermann, B.P. (1998) Personality disorders. In J. Engel Jr. & T.A. Pedley (Eds.) Epilepsy: A comprehensive textbook. Vol. II (pp.2065–2070). Philadelphia: Lippincott–Raven.
- Tremont, Geoffrey; Smith, Megan M; Bauer, Lyndsey; Alosco, Michael L; Davis, Jennifer D; Blum, Andrew S; LaFrance, W Curt (2012). "Comparison of personality characteristics on the Bear-Fedio Inventory between patients with epilepsy and those with non-epileptic seizures". The Journal of Neuropsychiatry and Clinical Neurosciences. 24 (1): 47–52. doi:10.1176/appi.neuropsych.11020039.
- Hughes, John R (2005). "The idiosyncratic aspects of the epilepsy of Fyodor Dostoevsky". Epilepsy & Behavior. 7 (3): 531–8. doi:10.1016/j.yebeh.2005.07.021. PMID 16194626.
- Roberts, JK; Robertson, MM; Trimble, MR (February 1982). "The lateralising significance of hypergraphia in temporal lobe epilepsy". Journal of Neurology, Neurosurgery, and Psychiatry. 45 (2): 131–8. doi:10.1136/jnnp.45.2.131. PMC . PMID 7069424.
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- Devinsky, Julie; Schachter, Steven (2009). "Norman Geschwind's contribution to the understanding of behavioral changes in temporal lobe epilepsy: the February 1974 lecture". Epilepsy & Behavior. 15 (4): 417–24. doi:10.1016/j.yebeh.2009.06.006. PMID 19640791.
- Dolgoff-Kaspar, R (et al.) (2011). "Numinous-like auras and spirituality in persons with partial seizures". Epilepsia. 52 (3): 640–6. doi:10.1111/j.1528-1167.2010.02957.x. PMID 21395568.
Epilepsy patients with frequent numinous-like auras have greater ictal and interictal spirituality of an experiential, personalized, and atypical form, which may be distinct from traditional, culturally based religiosity.
- Picard, Fabienne; Kurth, Florian (2014). "Ictal alterations of consciousness during ecstatic seizures". Epilepsy & Behavior. 30: 58–61. doi:10.1016/j.yebeh.2013.09.036. PMID 24436968. Lay summary.
Patients with ecstatic epileptic seizures report an altered consciousness, which they describe as a sense of heightened perception of themselves - they "feel very present"- and an increased vividness of sensory perceptions.
- Muhammed, Louwai (2013). "A retrospective diagnosis of epilepsy in three historical figures: St Paul, Joan of Arc and Socrates". Journal of medical biography. 21 (4): 208–11. doi:10.1177/0967772013479757.
- Nakken, Karl O; Brodtkorb, Eylert (2011). "[Epilepsy and religion]". Tidsskrift for den Norske lægeforening : tidsskrift for praktisk medicin, ny række. 131 (13-14): 1294–7. doi:10.4045/tidsskr.10.1049.
- Carrazana E. (et al.) (1999). "Epilepsy and Religious Experiences: Voodoo Possession". Epilepsia. 40 (2): 239–241. doi:10.1111/j.1528-1157.1999.tb02081.x. Lay summary – Epileptic seizures have a historical association with religion, primarily through the concept of spirit possession. Five cases where epileptic seizures were initially attributed to Voodoo spirit possession are presented. The attribution is discussed within the context of the Voodoo belief system.
- Stephen, M.D. Salloway (1997). "The Neural Substrates of Religious Experience". The Neuropsychiatry of Limbic and Subcortical Disorders. American Psychiatric Publications. ISBN 0880489421.
- Heilman, Kenneth M.; Valenstein, Edward (13 October 2011). Clinical Neuropsychology. Oxford University Press. p. 488. ISBN 9780195384871.
Studies that claim to show no difference in emotional makeup between temporal lobe and other epileptic patients (Guerrant et. al., 1962; Stevens, 1966) have been reinterpreted (Blumer, 1975) to indicate that there is, in fact, a difference: those with temporal lobe epilepsy are more likely to have more serious forms of emotional disturbance. This "typical personality" of temporal lobe epileptic patient has been described in roughly similar terms over many years (Blumer & Benson, 1975; Geschwind, 1975, 1977; Blumer, 1999; Devinsky & Schachter, 2009). These patients are said to have a deepening of emotions; they ascribe great significance to commonplace events. This can be manifested as a tendency to take a cosmic view; hyperreligiosity (or intensely professed atheism) is said to be common.
- LaPlante, Eve (22 March 2016). Seized: Temporal Lobe Epilepsy as a Medical, Historical, and Artistic Phenomenon. Open Road Distribution. p. 181. ISBN 9781504032773.
- Dewhurst, K; Beard, A W (1970). "Sudden religious conversions in temporal lobe epilepsy". The British Journal of Psychiatry. 117 (540): 497–507. doi:10.1192/bjp.117.540.497.
- Waxman, Stephen G, MD; Geschwind, Norman, MD (1972). "The Interictal Behavior Syndrome of Temporal Lobe Epilepsy". Archives of General Psychiatry. 32 (12): 1580–1586. doi:10.1001/archpsyc.1975.01760300118011. PMID 1200777. Lay summary – "Although the patient denied being religious, his writings contained numerous religious references, and some pages were adorned with religious symbols".
- Craig Aaen-Stockdale (2012). "Neuroscience for the Soul". The Psychologist. 25 (7): 520–523.
- Gerhard J. Luef (2008). "Epilepsy and sexuality". Seizure. 17 (2): 127–130. doi:10.1016/j.seizure.2007.11.009. Lay summary – Men and women with epilepsy frequently complain, if asked, of sexual dysfunction and appear to have a higher incidence of sexual dysfunction than persons with other chronic neurologic illnesses.
- Harden, Cynthia L (2006). "Sexuality in men and women with epilepsy". CNS spectrums. 11 (8 Suppl 9): 13–8. PMID 16871133.
- L Tebartz van Elsta (et al.) (2003). "Psychopathological profile in patients with severe bilateral hippocampal atrophy and temporal lobe epilepsy: evidence in support of the Geschwind syndrome?". Epilepsy & Behavior. 4 (3): 291–297. doi:10.1016/s1525-5050(03)00084-2. PMID 12791331. Lay summary – specific symptoms that characterize the Geschwind syndrome like hypergraphia and hyposexuality might be pathogenically related to hippocampal atrophy.
- Rees, Peter M; Fowler, Clare J; Maas, Cornelis (2007). "Sexual function in men and women with neurological disorders". Lancet. 369 (9560): 512–25. doi:10.1016/s0140-6736(07)60238-4. PMID 17292771.
- Devinsky, Orrin; Vorkas, Charles; Barr, William (2006). "Personality disorders in epilepsy". Psychiatric Issues in Epilepsy: A Practical Guide to Diagnosis and Treatment. Lippincott Williams & Wilkins. ISBN 078178591X.