Richard E. Davis and Ivan Osorio 1998;101;e4 DOI: 10.1542/peds.101.6.e4

Childhood Caffeine Tic Syndrome
Richard E. Davis and Ivan Osorio
Pediatrics 1998;101;e4
DOI: 10.1542/peds.101.6.e4
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located on the World Wide Web at:
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PEDIATRICS is the official journal of the American Academy of Pediatrics. A monthly
publication, it has been published continuously since 1948. PEDIATRICS is owned,
published, and trademarked by the American Academy of Pediatrics, 141 Northwest Point
Boulevard, Elk Grove Village, Illinois, 60007. Copyright © 1998 by the American Academy
of Pediatrics. All rights reserved. Print ISSN: 0031-4005. Online ISSN: 1098-4275.
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Childhood Caffeine Tic Syndrome
ABSTRACT. Objective. To determine whether caffeine ingestion was temporally correlated with tics in 2
healthy children.
Methods. Two first-degree cousins were observed
over a period of ;3 years, and the presence and absence
of tics was recorded and correlated with consumption of
or abstinence from caffeinated foods or beverages.
Results. Appearance and disappearance of tics were
closely and clearly temporally correlated with ingestion
and elimination of caffeine in the cousins’ diets.
Conclusions. Our observations suggest that caffeine
may precipitate tics in susceptible children. Pediatrics
1998;101(6). URL: http://www.pediatrics.org/cgi/content/
full/101/6/e4; caffeine, tics.
ABBREVIATION. CNS, central nervous system.
T
ics, a complex neurobehavioral disorder,1 manifest themselves as intermittent, transiently
suppressible involuntary movements affecting
4% to 24% of all children2 and 1% to 6% of the US
population.3 Although the pathophysiology of tics
and Tourette syndrome, of which they are a prominent manifestation, is not understood, these disorders can be treated successfully with dopamine receptor blocking drugs, a-2 adrenergic receptor
antagonists, or GABA receptor agonists.4 Review of
the pertinent literature yielded little in terms of
drugs or compounds that may exacerbate or precipitate tics; methylphenidate5–7 and cocaine8 have been
identified as capable of precipitating or worsening
tics in humans.
We describe two cases in which appearance and
disappearance of tics were correlated temporally
with consumption and discontinuation of caffeinated
beverages and foods and that raise the possibility
that this widely consumed central nervous system
(CNS) stimulant may worsen or trigger the appearance of tics in susceptible children.
CASE REPORT
Case 1
A 13-year-old white boy with normal development, IQ, and
physical/neurologic examination results began having daily tics
at age 7, characterized by intermittent, multiple involuntary contractions of facial and neck muscles. Tics were transiently suppressible by conscious effort, increased during periods of stress,
and absent during sleep. There were no vocal or phonic tics or
other manifestations of Tourette’s syndrome. These movements
had been present for some time but reached a disturbing level
during treatment with an antiallergy medication containing
pseudoephedrine. The tics improved but did not disappear after
this drug was discontinued. One of us (R.E.D.) observed that the
Received for publication Oct 20, 1997; accepted Feb 9, 1998.
Reprint requests to (R.E.D.) University of Kansas Medical Center, Comprehensive Epilepsy Center, 3901 Rainbow Blvd, Kansas City, KS 66160.
PEDIATRICS (ISSN 0031 4005). Copyright © 1998 by the American Academy of Pediatrics.
intensity of the tics corresponded with consumption of caffeinated
beverages (two to four daily) and multiple servings of chocolate.
After discussion with the parents, caffeine was excluded completely from his diet for 6 months, during which time the child
was free of tics. At the end of this period, caffeine was reintroduced in his diet in smaller amounts (three to seven soft drinks per
week) and the tics recurred. The persistence of tics paralleled
access to caffeine; 1 to 2 weeks after restricting caffeine completely
for the second time, the tics disappeared. The child remained
asymptomatic off caffeine for .2 years. Recent reexposure to
smaller amounts of caffeine (three to five soft drinks per week)
once again corresponded to the reappearance of tics. There are no
other manifestations of Tourette’s syndrome, and the boy continues to develop normally.
Case 2
An 11-year-old white boy, a first-degree cousin of the child
described in case 1, was noticed since age 6 to frequently and
without purpose contract facial and neck muscles in a repetitive
and somewhat stereotyped manner. These movements were
present on numerous occasions on a daily basis, and increased in
frequency if the child was anxious. He did not have phonic tics or
any other manifestations of Tourette’s syndrome. Development
and physical/neurologic examinations including IQ were normal.
Given that this child consumed two to four caffeinated beverages
and large amounts of chocolate every day and that tics disappeared in his cousin after caffeine restriction, the same recommendation was made to this child’s parents. Caffeine was excluded
completely from his diet, and ;2 weeks later the child was without tics for the first time since onset 2 years earlier. Several months
later, the tics recurred even though there was no apparent caffeine
consumption. However, on questioning the child admitted to
having restarted drinking caffeinated beverages. Exposure to caffeine continues to date, although at smaller doses (four to seven
soft drinks per week compared with two to four daily in the past),
and tics remain as a less frequent and intense isolated manifestation of abnormal motor behavior.
DISCUSSION
Tics may occur as an isolated phenomenon for
several weeks or months and remit spontaneously
and never recur.9 To establish more firmly a cause–
effect relationship, on two separate occasions over a
2-year period, one of these children was allowed
reexposure to caffeine. Reintroduction of this compound, although at lower doses than before, once
more exacerbated the abnormal movements, which
disappeared again only after complete restriction of
caffeine. This clear temporal relationship between
caffeine ingestion and tic recurrence imparts a causal
relationship. The other child reexposed himself initially (without his parents knowledge) to caffeine
and the motor tics reappeared. Although administration of pseudoephedrine aggravated the tics in the
first patient, this single exposure is insufficient to
establish a cause– effect relationship. A literature
search did not reveal any cases of tics aggravated or
precipitated by pseudoephedrine.
Caffeine is the CNS stimulant used most widely by
persons of all ages, and it is readily available to
children in our culture today, especially in soft
drinks and certain foods (Table 1).10 –12 Caffeine
crosses the blood– brain barrier very rapidly, and its
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1 of 2
TABLE 1. Caffeine Content of Popular Beverages and Foods
Source
Beverages
Coffee (5 oz)
Brewed, drip
Brewed, percolated
Instant
Decaffeinated brewed
Decaffeinated instant
Soft drinks (12 oz)
Mountain Dew
Surge
Coca-Cola, Diet Coca-Cola
Dr Pepper, Diet Dr Pepper
Pepsi-Cola
Diet Pepsi-Cola
7-Up, Sprite
Tea (5 oz)
Brewed, imported brands
Brewed, US brands
Instant
Iced (12 oz)
Foods
Chocolate
Baker’s chocolate (1 oz)
Dark chocolate, sweet semisweet (1 oz)
Milk chocolate (1 oz)
Chocolate milk (8 oz)
Over-the-counter drugs
Anacin
Dexatrim
Excedrin
Nodoz
Vivarin
Mean Caffeine
Content (mg)
115–137
80–117
60–65
3
2–3
54
52
45–46
41
38
36
0
60
40–46
30
70
25–26
20
6
5
32
200
65
100
200
concentration in brain is highly correlated with that
in plasma.10 There is evidence that caffeine stimulates
motor activity10 and that children are particularly
susceptible to this effect.13,14 Pharmacologically induced akinesia in rats was reverted in a dosedependent manner by caffeine,15 an effect that has
been interpreted as reflective of dopamine mimetic
activity of this methylxanthine. Given that dopamine
receptor blockers such as haloperidol have a suppressant action on tics,4 and although the pathophysiology of this disorder has not been established, it is
likely that the dopaminergic system modulates or
facilitates their expression. Therefore, it is probable
that an agent, such as caffeine, with dopamine mimetic activity would exacerbate tics. An extensive
literature review did not yield any human or animal
reports on the role of caffeine on abnormal motor
behavior, such as tics. This observation and previous
findings that other CNS stimulants,5– 8 such as methylphenidate or cocaine, precipitate or worsen tics or
2 of 2
Tourette’s syndrome suggest that the expression of
this motor phenomena is susceptible to chemical influences. Clarification of the potential role of chemical precipitants such as caffeine would further the
development of preventive therapies for tics, decreasing the reliance on pharmacologic treatments,
which may have long-term adverse effects, while
increasing our understanding of the pathophysiology of this disorder and of the role that chemicals
may play in its expression. A large, double-blind
crossover study to investigate the role of caffeine and
other nonprescription compounds in the expression
of tics should yield valuable information.
Richard E. Davis, MD
Ivan Osorio, MD
University of Kansas Medical Center
Comprehensive Epilepsy Center
Kansas City, KS 66160
ACKNOWLEDGMENT
We thank James Watkins for reviewing the manuscript.
REFERENCES
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11. FDA Consumer. Rockville, MD: Dept of Health and Human Services
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Commonly Used. 14th ed. Philadelphia, PA: JB Lippincott; 1985
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normal prepubertal boys. Am J Psychiatry. 1981;138:178 –183
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15. Popoli P, Caporali MG, Scotti-de-Carolis A. Akinesia due to catecholamine depletion in mice is prevented by caffeine. Further evidence for
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CHILDHOOD CAFFEINE TIC SYNDROME
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Childhood Caffeine Tic Syndrome
Richard E. Davis and Ivan Osorio
Pediatrics 1998;101;e4
DOI: 10.1542/peds.101.6.e4
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PEDIATRICS is the official journal of the American Academy of Pediatrics. A monthly
publication, it has been published continuously since 1948. PEDIATRICS is owned, published, and
trademarked by the American Academy of Pediatrics, 141 Northwest Point Boulevard, Elk Grove
Village, Illinois, 60007. Copyright © 1998 by the American Academy of Pediatrics. All rights
reserved. Print ISSN: 0031-4005. Online ISSN: 1098-4275.
Downloaded from pediatrics.aappublications.org by guest on August 22, 2014