Transcranial magnetic stimulation, where magnetic pulses are delivered non-invasively through the skull to excite particular regions of the brain, is a promising technique with applications that could range from boosted memories to reduced food cravings. Now, scientists exploring its potential to tackle drug addiction have found that it can dampen brain activity in response to common triggers, with implications for both the development of new substance abuse treatments and our understanding of neuroscience.

Decades of research has seen addiction categorized as a form of brain disease, though not all experts subscribe to that school of thought. In any case, scientists so far haven't been able to intervene in the brain's neural circuitry to dampen substance dependence, but now researchers at Medical University of South Carolina believe they may have a way in.

The discovery centers on what is known as cue reactivity, which refers to elevated brain activity in response to particular triggers. In terms of addiction to things like alcohol and nicotine, for example, these cues could take the form of a liquor bottle or the sight of someone smoking.

For their study, the scientists enlisted 25 people with cocaine addiction and 24 people with alcohol addiction. The subjects were treated as individual groups, each receiving transcranial magnetic stimulation (TMS) that targeted the ventromedial prefrontal cortex, a part of the brain central to cue reactivity driven by drug-taking behaviors.

The treatments consisted of a real stimulation session along with a fake one that simply simulated TMS without actually stimulating the brain, with all subjects' brains imaged before and after. The team found that when both groups were shown images of their respective cues, reactivity was significantly reduced following the single TMS session.

While they have uncovered a potential one-off neural mechanism for substance use, whether the TMS treatment works on a larger scale and actually lowers consumption of drugs and alcohol in a meaningful way is not yet clear. While it reduced cue reactivity, the subjects reported that the single TMS sessions didn't alter their drug or alcohol cravings thereafter, and the scientists say further experiments involving repeated sessions will be needed to see if the technique can achieve such an outcome.

An ongoing clinical trial is currently exploring this by exposing cocaine users to multiple TMS sessions, but the researchers say the discovery could have consequences outside of advanced new treatments for drug and alcohol abuse. Cue reactivity is a symptom of many diseases, including post-traumatic stress disorder, generalized anxiety disorder and traumatic brain injury.

"Therefore, the treatment described in this manuscript may have implications far beyond the substance abuse field," says senior author Colleen Hanlon.

The research was published in the journal Biological Psychiatry: Cognitive Neuroscience and Neuroimaging.

Source: Elsevier