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SAN DIEGO -- Magnetic brain stimulation with a sensory cue was associated with reduced smoking rates and improved quit rates among heavy smokers unaffected by prior therapy, researchers reported here.

Nearly half (44%) of the heavy smokers who received high-frequency (10 Hz) repetitive transcranial magnetic stimulation preceded by a smoking cue were able to quit smoking compared with only 25% of those give no smoking cue, low-frequency (1 Hz) stimulation, or sham treatment (about 13% for the latter two arms), according to , of Ben-Gurion University in Beer-Sheva, Israel, and colleagues.

Some three-quarters of participants who received high-frequency stimulation and cue had a reduction in cigarettes smoked of 50% or more following 13 sessions of magnetic brain stimulation, Abraham said during an oral presentation at the Society for Neuroscience meeting.

Abraham noted that transcranial magnetic stimulation is an FDA approved treatment for depression. The therapy has also shown efficacy in stroke rehabilitation, Alzheimer's disease, and migraines, among other conditions. Magnetic stimulation may also help boost long-term recall.

He also pointed out that animal studies of addiction have shown behavioral and neurochemical response from repeated stimulation of the prefrontal cortex, offering a noninvasive way to alter the brain circuitry associated with addiction and to "alter craving-induced neuro-adaptation."

To evaluate the effect of high-frequency and low-frequency deep repeated transcranial magnetic stimulation in human nicotine addiction, the authors enrolled 115 heavy smokers (ages 21-70) who smoked at least 20 cigarettes a day and who were motivated to quit smoking, but who had tried -- and failed -- to stop through other means.

Stimulation was applied to the prefrontal cortex and the insula through a coil the researchers created especially for this study.

Participants were randomized to receive sham stimulation, low-frequency stimulation, or high-frequency stimulation over 13 sessions. These groups were further divided by randomly priming some participants in each group by having them observe a person smoking in front of them prior to receipt of treatment.

Researchers measured participants' urine cotinine levels and self reports of smoking incidence. Dependence and craving were measured through questionnaires, while impulsivity was measured with neurocognitive tests. Participants also reported outcomes at 6 months of follow-up.

There was no significant difference between low-frequency treatment and sham treatment after 6 months. However, priming of participants who received placebo stimulation and lack of priming in participants with low-frequency stimulation were associated with similar quit rates (about 13%), while lack of priming in the 0 Hz recipients and priming in those who received 1 Hz stimulation was associated with a 0% quit rate.

At follow-up, lack of priming was associated with a roughly 25% quit rate among those who received high-frequency stimulation, which was still smaller than the 33% who were primed and remained smoke-free at 6 months.

"High frequency treatment reduced self-reported cigarette consumption, cotinine levels in urine, and nicotine dependence" in both the short- and long-term, Abraham noted, adding that stimulation offers an alternative treatment option to patients who've failed prior therapies for smoking cessation.

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