By Ernie Hood
Electrical brain stimulation is a new frontier in treatments of psychiatric disorders, as we saw in a post last October. Several different types of brain stimulation are already FDA-approved and in clinical use for conditions such as depression.
Now, researchers are exploring one particular type of brain stimulation called transcranial magnetic stimulation (TMS) as a treatment for cocaine addiction. Preliminary studies by Dr. Diana Martinez of Columbia University and others suggest that TMS may substantially alter cocaine use in addicted people. In the pilot study she recently conducted, TMS appears to have positive long-term effects compared to placebo or sham treatment.
In the study, cocaine addicts were brought into the laboratory and offered a choice between a small dose of cocaine and a small sum of money, in this case $5, which was actually worth more than the cocaine—weighting the choice toward the money. “We just look at how many times they choose cocaine, and then we do an intervention with TMS and repeat the cocaine self-administration procedure,” said Martinez. With such a direct outcome measure, it doesn’t take very many subjects to yield tangible results. “We can get an idea with a very small number whether or not there’s a signal.”
After considerable experimentation to determine the most effective and most tolerable TMS settings, a signal did indeed emerge, suggesting that the neural targets and frequency and duration of the TMS sessions were having an impact on cravings. “What we’re trying to do is approach addiction with more of a learning or information processing point of view, rather than a hedonistic point of view, and it seems to be working,” Martinez explained. Much work remains to further refine the technology, but the results of the small pilot study were promising.
The coil counts
One of the innovations in Martinez’s technique is the use of a different electromagnetic coil, the element of the treatment that determines where in the brain the stimulation will go. She uses the so-called “H” coil, which allows deep penetration into neurons where the addiction response is believed to originate.
The experimental coil is not currently in commercial use, but when Martinez approached the company that makes TMS equipment, they were quick to respond. “They immediately sent us a whole set-up and a whole system to support us doing this research,” she said. Martinez said that given what appears to be little interest in the pharmaceutical industry in developing pharmacological agents to treat addiction (an avenue Martinez has attempted to pursue in the past), she is optimistic that her research and others working on TMS may reap dividends in use of gentle, noninvasive brain stimulation as a treatment modality.
“What we need to do now,” she noted, “is get funding to do a much bigger clinical trial.” She is currently working on grant applications, and hopes that soon she will have the opportunity to test the technique in many more cocaine addicts, offering new hope to combat a notoriously intransigent addiction.