A stereotypy (//, "STAIR-ee-oh-TEYE-pee") is a repetitive or ritualistic movement, posture, or utterance. Stereotypies may be simple movements such as body rocking, or complex, such as self-caressing, crossing and uncrossing of legs, and marching in place. They are found in people with intellectual disabilities, autism spectrum disorders, tardive dyskinesia and stereotypic movement disorder; studies have shown stereotypies associated with some types of schizophrenia. Frontotemporal dementia is also a common neurological cause of repetitive behaviors and stereotypies. Several causes have been hypothesized for stereotypy, and several treatment options are available.
Stereotypy is sometimes called stimming in autism, under the hypothesis that it self-stimulates one or more senses. Related terms include punding and tweaking to describe repetitive behavior that is a side effect of some drugs.
Among people with frontotemporal lobar degeneration, more than half (60%) had stereotypies. The time to onset of stereotypies in people with frontotemporal lobar degeneration may be years (average 2.1 years).
Distinction from tics
Like tics, stereotypies are patterned and periodic, and are made worse by fatigue, stress, and anxiety. Unlike tics, stereotypies usually begin before the age of three, involve more of the body, are more rhythmic and less random, and are associated more with engrossment in another activity rather than premonitory urges. Examples of early tics are things like blinking and throat clearing, while arm flapping is a more common stereotypy. Stereotypies do not have the ever-changing, waxing and waning nature of tics, and can remain constant for years. Tics are usually suppressible for brief periods; in contrast, children rarely consciously attempt to control a stereotypy, although they can be distracted from one.
There are several possible explanations for stereotypy, and different stereotyped behaviors may have different explanations. A popular explanation is stimming, which hypothesizes that a particular stereotyped behavior has a function related to sensory input. Other explanations include hypotheses that stereotypy discharges tension or expresses frustration, that it communicates a need for attention or reinforcement or sensory stimulation, that it is learned or neuropathological or some combination of the two, or that it is normal behavior with no particular explanation needed.
Punding is a term that was coined originally to describe complex prolonged, purposeless, and stereotyped behavior in chronic amphetamine users; it was later described in Parkinson's disease. Punding is a compulsion to perform repetitive mechanical tasks, such as sorting, collecting, or assembling and disassembling common items. Punding may occur in individuals with Parkinson's disease treated with dopaminergic agents such as L-DOPA.
Stereotypies also occur in non-human animals. It is considered an abnormal behavior and is sometimes seen in captive animals, particularly those held in small enclosures with little opportunity to engage in more normal behaviors. These behaviors may be maladaptive, involving self-injury or reduced reproductive success, and in laboratory animals can confound behavioral research. Examples of stereotypical behaviors include pacing, rocking, swimming in circles, excessive sleeping, self-mutilation (including feather picking and excessive grooming), and mouthing cage bars. Stereotypies are seen in many species, including primates, birds, and carnivores. Up to 40% of elephants in zoos display stereotypical behaviors. Stereotypies are well known in stabled horses, usually developing as a result of being confined, particularly with insufficient exercise. They are colloquially called stable vices. They present a management issue, not only leading to facility damage from chewing, kicking, and repetitive motion, but also lead to health consequences for the animal if not addressed.
Stereotypical behaviors are thought to be caused ultimately by artificial environments that do not allow animals to satisfy their normal behavioral needs. Rather than refer to the behavior as abnormal, it has been suggested that it be described as "behavior indicative of an abnormal environment." Stereotypies are correlated with altered behavioral response selection in the basal ganglia. As stereotypies are frequently viewed as a sign of psychological distress in animals, there is also an animal welfare issue involved.
Stereotypical behavior can sometimes be reduced or eliminated by environmental enrichment, including larger and more stimulating enclosures, training, and introductions of stimuli (such as objects, sounds, or scents) to the animal's environment. The enrichment must be varied to remain effective for any length of time. Housing social animals with other members of their species is also helpful. But once the behavior is established, it is sometimes impossible to eliminate due to alterations in the brain.
- Jankovic J. Differential diagnosis and etiology of tics. Adv Neurol. 2001;85:15–29. PMID 11530424.
- Pedro BM, Pilowsky LS, Costa DC, et al.. Stereotypy, schizophrenia and dopamine D2 receptor binding in the basal ganglia. Psychol Med. 1994;24(2):423–9. doi:10.1017/s0033291700027392. PMID 8084937.
- Mateen FJ, Josephs KA (June 2009). "The clinical spectrum of stereotypies in frontotemporal lobar degeneration". Movement Disorders 24 (8): 1237–40. doi:10.1002/mds.22555. PMID 19412926.
- Mendez MF, Shapira JS (March 2008). "The spectrum of recurrent thoughts and behaviors in frontotemporal dementia". CNS Spectr 13 (3): 202–8. PMID 18323753.
- Singer HS. Motor stereotypies [PDF]. Semin Pediatr Neurol. 2009;16(2):77–81. doi:10.1016/j.spen.2009.03.008. PMID 19501335.
- Nind M, Kellett M. Responding to individuals with severe learning difficulties and stereotyped behaviour: challenges for an inclusive era. Eur J Spec Needs Educ. 2002;17(3):265–82. doi:10.1080/08856250210162167.
- Weisheit RA. Methamphetamine and violence in Illinois [PDF]. Illinois Criminal Justice Information Authority; [Retrieved 2009-12-08].
- Muthugovindan D, Singer H. Motor stereotypy disorders. Current Opinion in Neurology. 2009;22(2):131–6. doi:10.1097/WCO.0b013e328326f6c8. PMID 19532036.
- Evans AH, Katzenschlager R, Paviour D et al. Punding in Parkinson's disease: its relation to the dopamine dysregulation syndrome. Mov Disord. 2004;19(4):397–405. doi:10.1002/mds.20045. PMID 15077237.
- Fernandez HH, Friedman JH (September 1999). "Punding on L-dopa". Mov. Disord. 14 (5): 836–8. doi:10.1002/1531-8257(199909)14:5<836::AID-MDS1018>3.0.CO;2-0. PMID 10495047.
- Jankovic J (2005). "Motor fluctuations and dyskinesias in Parkinson's disease: clinical manifestations". Mov. Disord. 20 Suppl 11: S11–6. doi:10.1002/mds.20458. PMID 15822109.
- O'Sullivan SS, Evans AH, Lees AJ (2009). "Dopamine dysregulation syndrome: an overview of its epidemiology, mechanisms and management". CNS Drugs 23 (2): 157–70. doi:10.2165/00023210-200923020-00005. PMID 19173374.
- Buxton JA, Dove NA (June 2008). "The burden and management of crystal meth use". CMAJ 178 (12): 1537–9. doi:10.1503/cmaj.071234. PMC 2396355. PMID 18519899.
- "Selected Intelligence brief: methamphetamine myths". U.S. Drug Enforcement Administration. XXXVIII (2). February 2005. Reprinted with permission from the NDIC Narcotics Digest Weekly 2005;4(2):1
- Garner JP, Mason GJ. Evidence for a relationship between cage stereotypies and behavioural disinhibition in laboratory rodents. Behav Brain Res. 2002;136(1):83–92. doi:10.1016/S0166-4328(02)00111-0. PMID 12385793.
- Stern A. Elephant deaths at zoos reignite animal debate. 2005-02-28 [Retrieved 2006-05-30]. Reuters.
- Christie, Julie Christie, (2008). "Horse Behavior and Stable Vices" (PDF). University of Minnesota Extension (Regents of the University of Minnesota).
- Chinthapalli V. M.; Singer H. S. Stereotypies of infancy and childhood., April 19, 2010. Retrieved on November 30, 2010.
- Photo & video library of stereotypic behavior in captive animals