High-frequency repetitive transcranial magnetic stimulation decreases cigarette smoking
High-Frequency rTMS Decreases Cigarette Smoking
High-Frequency Repetitive Transcranial Magnetic Stimulation Decreases Cigarette Smoking Peter Eichhammer, M.D.; Monika Johann, M.D.; Alexander Kharraz, M.D.; Harald Binder, M.A.; David Pittrow, M.D.; Norbert Wodarz, M.D.; and Göran Hajak, M.D.
epetitive transcranial magnetic stimulation (rTMS)
R is a new technique that has been found to be
useful as a potential treatment for neuropsychiatricdiseases.1 With regard to the neurobiological mechanismsinvolved, there is compelling evidence that rTMS causes
Background: The mesolimbic dopaminergic
changes in neuronal circuits. Such alterations include se-
reward system seems to play a crucial role in re-
lected local modifications in the dynamic release patterns
inforcing effects of nicotine. Recently, acute high-frequency repetitive transcranial magnetic stimu-
of biogenic amines and amino acids.2 Using intracerebral
lation (rTMS) of frontal brain regions has been
microdialysis in rodents, stimulation of dopamine release
shown to efficiently modulate the mesostriatal
could be demonstrated in the dorsal hippocampus as well
and mesolimbic dopaminergic system in both
as in the shell of the nucleus accumbens.3 These data pro-
animals and humans. For this reason, we investi-
vide compelling in vivo evidence that acute high-frequency
gated whether high-frequency rTMS would beable to influence nicotine-related behavior by
rTMS of frontal brain regions has a modulatory effect on
studying rTMS effects on craving and cigarette
both the mesolimbic and the mesostriatal dopaminergic
systems. Moreover, these findings are fairly compatible
Method: Fourteen treatment-seeking smokers
with data showing that high-frequency rTMS of the human
were included in a double-blind crossover trial,
prefrontal cortex induces dopamine release in the caudate
conducted in 2002, comparing single days ofactive versus sham stimulation. Outcome mea-
nucleus.4 For this reason, high-frequency rTMS is consid-
sures were rTMS effects on number of cigarettes
ered to be especially useful in neuropsychiatric disorders
smoked during an ad libitum smoking period
associated with subcortical dopamine dysfunction.2–4
and effects on craving after a period of acute
The primary subjective and physiologic effects of smok-
ing are known to result from the central actions of nico-
Results: High-frequency (20-Hz) rTMS of left
dorsolateral prefrontal cortex reduced cigarette
tine.5,6 In this context, the mesolimbic dopaminergic reward
smoking significantly (p < .01) in an active
system seems to play a pivotal role in reinforcing effects of
stimulation compared with sham stimulation.
nicotine.6,7 Decreased function in brain reward systems dur-
Levels of craving did not change significantly.
ing nicotine withdrawal seems to be closely associated with
Conclusion: High-frequency rTMS may be
craving, relapse, and continued nicotine consumption.8 For
useful for treatment in smoking cessation. (J Clin Psychiatry 2003;64:951–953)
this reason, modulation of dopaminergic neurotransmissionmight serve as a potential target for treating tobacco addic-tion. Additional support for this hypothesis comes fromstudies with bupropion, an atypical antidepressant block-
Received Oct. 4, 2002; accepted Feb. 14, 2003. From the Department
ing neuronal uptake of dopamine, which has recently been
of Psychiatry and Psychotherapy, University of Regensburg,
approved as a treatment for smoking cessation.9,10
Considering that high-frequency rTMS has been shown
The authors report no financial affiliation or other relationshiprelevant to the subject matter of this article.
to alter dopaminergic neurotransmission in subcortical
Corresponding author and reprints: Peter Eichhammer, M.D.,
structures, we investigated whether 20-Hz rTMS is able to
Department of Psychiatry and Psychotherapy, University of RegensburgUniversitaetsstrasse 84, 93053 Regensburg – Germany
reduce cigarette smoking and craving. (e-mail: peter.eichhammer@bzk.uni-regensburg.de).
Fourteen right-handed probands who wished to quit
smoking were recruited through advertisement in 2002. COPYRIGHT 2003 PHYSICIANS POSTGRADUA TE PRESS, INC. COPYRIGHT 2003 PHYSICIANS POSTGRADUATE PRESS, INC. Table 1. Baseline Demographics and Smoking Characteristics Figure 1. Effect of High-Frequency Repetitive Transcranial of 14 Treatment-Seeking Probandsa Magnetic Stimulation on the Number of Cigarettes Smoked (mean ± SD) During an Ad Libitum Smoking Phase of 6
aValues shown as mean ± SD unless otherwise noted. Abbreviation: FTND = Fagerström Test for Nicotine Dependence.
Subjects were regular cigarette smokers (12 female,
2 male) aged 23 to 55 years. Smoking characteristics
(Table 1) were comparable to those reported in other stud-ies investigating therapeutics for nicotine addiction.11 All
*Denotes significant difference from sham stimulation (p < .01).
candidates received a structured clinical interview com-bined with a short physical examination and completedseveral questionnaires, including the Fagerström Test
administered at baseline and 30 minutes after rTMS treat-
of Nicotine Dependence (FTND)11 as well as a drug and
ment. Using this scale, the subjective state “desire to
health history questionnaire. Standard cut-off thresholds
smoke” was assessed, as it has been done earlier in a study
were used to eliminate those persons with significant
on naltrexone alteration of acute smoking response.13
current or past alcohol, drug, or psychiatric symptoma-
“Desire to smoke” ratings have been shown to be sensitive
tology.12 Subjects were also excluded for positive urine
to assess self-reported levels of craving.14 Number of ciga-
toxicology (cocaine, opiates, amphetamines, benzodiaze-
rettes smoked was noted during an ad libitum smoking
pines). All candidates abstained from smoking 12 hours
phase (6-hour period) after rTMS treatment. The subjects
before each rTMS session and gave written informed con-
were instructed to smoke freely using their own chosen
sent to take part in the study, which was approved by the
brand of cigarettes. Data were obtained under natural
conditions in the subjects’ normal living or working envi-ronment, not under laboratory conditions, since environ-
mental and other contextual factors have been shown to
Within a crossover design, each subject received 2
decisively influence individual smoking behavior.15 For
trials of active and 2 trials of sham stimulation in a ran-
this reason, subjects had to keep a daily diary 3 weeks be-
domized order on 4 consecutive days. Patients and clinical
fore entering the study in order to check compliance and
staff were unaware of stimulation condition. On each
accurate assessment of numbers of cigarettes smoked.
study day, sessions started in the early afternoon (1 p.m.). The participants received 20 trains of rTMS at a rate of 20
Hz for 2.5 seconds over 14 minutes (1000 pulses/session;
Each subject participated in several trials, so we ex-
intertrain interval: 42.5 seconds) by means of a repetitive
pected a repeated-measures covariance structure of the
magnetic stimulator (Magstim Co., Whitland, Dyfed,
data. Instead of the more traditional repeated-measures
U.K.). Stimulation site was the left dorsolateral prefrontal
analysis of variance, we used a linear mixed-effects model
cortex, defined as 5 cm anterior and in a parasagittal plane
for data analysis. This class of statistical models allows for
from the point of maximum stimulation of the abductor
more flexibility in model construction and selection.16 In
pollicis muscle. Stimulation intensity was at 90% of motor
this context, using this linear mixed-effects model enabled
threshold. Sham stimulation was given at the same loca-
us to judge whether an order effect of stimulation condi-
tion and frequency by using a sham-coil system (Magstim,
tions (active stimulation/sham stimulation) should be in-
U.K.). The stimulation paradigm was identical with stimu-
cluded in the model, on the basis of objective statistical
lation conditions leading to a marked dopamine release in
criteria. The threshold for significance was set at p < .05.
mesolimbic structures such as the nucleus accumbens.2,3
Two outcome measures were used. Craving was mea-
Using a linear mixed-effects model for data analysis,
sured with a 10-cm–long, 100-point visual analogue scale
group membership (active vs. sham stimulation) was the
COPYRIGHT 2003 PHYSICIANS POSTGRADUATE PRESS, INC. COPYRIGHT 2003 PHYSICIANS POSTGRADUATE PRESS, INC.
High-Frequency rTMS Decreases Cigarette Smoking
fixed-effect covariate and subject ID was included as a
support further investigation of high-frequency rTMS for
The fixed group effect was found to be significant
(p < .01) for “number of cigarettes smoked” (95%
Drug names: bupropion (Zyban and others), naltrexone(ReVia and others).
CI = 1.301 to 5.109) but not for “craving.” The directionof the effect indicated that the number of cigarettes
smoked was significantly smaller under active stimula-tion conditions compared with sham stimulation condi-
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