About 15 percent of all people come down with depressions at some point of life. Psychotherapy and/or drugs normally help most of those patients. But there are so-called “therapy-resistant” patients – no treatment helps them. For the patient, this means they are trapped in their grey, gloomy world. Suicide is quite a common consequence. But now there is a new ray of hope on the horizon for those patients: the deep brain stimulation.
Rewarding and anticipation start in the brain
So far, this method has been used successfully on Morbus Parkinson patients and people with epilepsy. Patients showed a brightened spirit in many cases. This inspired the study group of Professor Thomas Schläpfer in Bonn to implant electrodes in selective parts of the brain of depressive people to influence the disease by stimulating with electric impulses. But where in these complicated convolutions of the brain should they start? Current researches concentrate mainly on two particular regions of the brain. “But we stimulated a third region – the so-called Nucleus accumbens”, explains Thomas Schläpfer, psychiatrist in Bonn and, together with his colleague Professor Volker Sturm of the University Hospital Cologne, head of the studies.
The Nucleus accumbens is a structure the size of a hazelnut in the reward center of the brain. This particular center is profoundly important, because it tells us that what we are doing is good for us. Here we memorize positive experience and start anticipation. Schläpfer explains: “Very often, depressive people are inactive and not capable of enjoying. There are manifested indications, that the Nucleus accumbens plays a key role in the genesis of this disease.”
It works within minutes
With this knowledge in their luggage, the researchers started working and began with three patients – two men and one woman – to stimulate the reward center with electrodes. All the patients suffered severely from deepest depressions for years and without any hope or help from common treatment methods.
“The brain of each patient was exactly measured by a high resolution MRI to avoid any injuries of the difficile brain structures” explains Schläpfer. On the basis of this card accurate to the millimetre, they laid the fine cables through the cerebral cortex to the Nucleus accumbens. Here they placed two electrodes to restore the function of the reward center. The pulser is implanted in the chest providing the stimuli. And the effect shows almost immediately after the first given impulses.
Patients trapped in deepest depressions and barely capable of any activity, all of a sudden showed interest in the world around them and started planning activities. “Only one minute after the stimulation had started, one of the patients announced that he planned to ascend the Cologne Cathedral. And the very next day he did it”, reports Schläpfer. But also the treated woman tells the scientists that she is enjoying bowling again. And the researchers confirm the good results. Within a fortnight, the values on the Hamilton depression index reduced from 43 to 25 and from 35 to 25 and 20. A change in the flow of blood and metabolism was proven by PET.
Hope for a better life
But to go off proved to be impossible, because as soon as the pulser stopped giving signals, the depression returned with all its might. “To turn it off was just not ethical, the Bonn psychiatrist said. Except a little pain in the wound in the beginning, no further undesirable effects were recorded. However, the physician qualifies, that these are pre-tests only and the number of patients was too small to draw general and final conclusions. Further experiments showed that obviously not every patient responds to this method. In addition, each and every surgery in the brain is very risky and not suitable for every patient. The experiments with pulsers will continue in the time to come – also to clarify which patients benefit from this complex method in the depths of the brain. But nonetheless – the resume is positive. “We can give those seriously ill and even those therapy-resistant the chance to participate in life again” resumes Schläpfer.
The results of those pre-tests are relevant enough in the professional world for a publication in the prestigious magazine Neuropsychopharmacology.