Somnambulism is a parasomnia consisting of complex motor behaviours during deep non-rapid eye movement sleep.Recent studies suggest that the main cause for sleepwalking is an abnormal activity of serotonergic neurons in the raphe nuclei in the brain stem, which leads to an increased amount of serotonin. In patients with somnambulism, the regulatory mechanism mediated by 5-HT1 inhibitory autoreceptors is disturbed and the activity of serotonergic neurons remains increased. Repolarization (through the mechanism of negative feedback) is impaired due to abnormally high serotonin levels. The condition is more commonly observed in children than in adults. In about 80% of the somnambulism cases, a family member is reported to also be affected. Episodes of sleepwalking are observed as a side effect of some medications such as Zolpidem and Risperidone.
Grzegorz R. Juszczak, Artur H. Swiergiel, Serotonergic hypothesis of sleepwalking, Medical Hypotheses, Volume 64, Issue 1, 2005, Pages 28-32, ISSN 0306-9877, https://doi.org/10.1016/j.mehy.2004.06.013. (http://www.sciencedirect.com/science/article/pii/S0306987704003925)
Piryova, B., Nachev, N. Human physiology, “Regulation of wakefulness and sleep” Publishing House Arso, Sofia, 2006
G Aghajanian, R-J Liu, “Serotonin (5-Hydroxytryptamine; 5-HT): CNS Pathways and Neurophysiology”, (2009)
Popat, S., Winslade, W. While, “You Were Sleepwalking: Science and Neurobiology of Sleep Disorders & the Enigma of Legal Responsibility of Violence During Parasomnia.” Neuroethics 8, 203–214 (2015). https://doi.org/10.1007/s12152-015-9229-4
Antonio Zadra, Alex Desautels, Dominique Petit, Jacques Montplaisir, Somnambulism: clinical aspects and pathophysiological hypotheses, The Lancet Neurology, Volume 12, Issue 3, 2013, Pages 285-294, ISSN 1474-4422, https://doi.org/10.1016/S1474-4422(12)70322-8. (http://www.sciencedirect.com/science/article/pii/S1474442212703228)
Rosemarie Perrault, Julie Carrier, Alex Desautels, Jacques Montplaisir, Antonio Zadra, Electroencephalographic slow waves prior to sleepwalking episodes, Sleep Medicine, Volume 15, Issue 12, 2014, Pages 1468-1472, ISSN 1389-9457, https://doi.org/10.1016/j.sleep.2014.07.020. (http://www.sciencedirect.com/science/article/pii/S1389945714004110)
Juszczak, Grzegorz. (2011).
Desensitization of GABAergic receptors as a mechanism of zolpidem-induced somnambulism. Medical hypotheses. 77. 230-3. 10.1016/j.mehy.2011.04.019.
Najmi A, Siddiqui F, Ray A, et al. (March 10, 2020) Risperidone-induced Somnambulism: A Case Report and Brief Review of Literature. Cureus 12(3): e7238. DOI 10.7759/cureus.7238
