A Dunedin-based neurosurgeon is investigating whether tiny devices implanted in the brain can stop alcoholics' cravings.

The study, led by the University of Otago's Professor Dirk De Ridder, is the first in the world to use implants to target cravings processes in the brain to combat alcoholism and, if successful, could result in a new form of intervention.

This week, De Ridder, a neurosurgeon at Dunedin Hospital who also heads the country's first academic neurosurgery unit, inserted implants in two patients from Christchurch, bringing the number of participants in his study to six.

The target we are using overlaps with an area in the brain that also involves stress, so it has benefits for cravings and stress.

By the end of the year, he hoped to have recruited 10 patients.


He is also introducing newly redesigned implants, cutting-edge neuro-stimulators specially made for the trials by US-based St Jude Medical, which allow him to study a wider range of signals sent from the implant to specific circuits in the brain that controlled cravings.

"Basically, it means that I've now got more languages with which to communicate with the brain, which hopefully should improve the outcome."

The technology is aimed at those whose health had been severely impaired by alcohol, and who had tried every other non-surgical treatment available.

Over recent times, scientists have increasingly been exploring whether subtly electrically stimulating certain parts of the brain could inhibit signals that fuelled cravings.

"The main problem with current stimulators is that they are derived from pacemaker technology, and the heart is a relatively simple organ to stimulate, whereas the brain is somewhat more complex.

"That's why we've had to push the technology to create the bigger versatility - or enable more languages - that might improve the result."

Researchers in Germany have trialled implants to combat alcohol addiction but most of the participants had relapsed.

However, that study had targeted reward processes in the brain, rather than cravings, he said.


Cravings, stress and cues - such as walking past a bar or seeing alcohol in the supermarket - were the three main reasons why 80 per cent of people with alcohol addictions relapsed.

"So you have to target one of those three. You can't do anything about cues, and you can treat stress but that probably isn't so efficient, so that's why we opted to go after cravings.

"But the interesting thing is the target we are using overlaps with an area in the brain that also involves stress, so it has benefits for cravings and stress."

Results of the study have so far been promising: none of the participants have abused alcohol since surgery, and two had also been able to quit smoking.

The intervention also appeared to show positive effects on obsessive compulsive disorder, which was affected by the same brain circuitry as addiction.

"We are now getting closer to a 75 per cent improvement rate in 75 per cent of the patients, but of course, because the numbers are so small, one or two extra patients who don't respond very well can change that.


"Ideally, we'd like to get a 100 per cent improvement rate, but realistically, something around the 75 or 80 per cent mark is really what we are trying to obtain."

De Ridder planned to present the preliminary results of the study to a conference in Barcelona next year.

If promising enough, it would be widened to include many more patients and research centres overseas.