In search of new treatments for mental illness
Transcranial magnetic stimulation is a recommended treatment option for depression. Robert Bodén is now going to evaluate whether the method is also effective against voice hallucinations, depression in teenagers and eating disorders. He also plans to explore alternative ways of treating mental illness using the new technique of focused ultrasound.
Patients come to the brain stimulation clinic at Uppsala University Hospital for treatment for depression. The visit itself only takes a few minutes, but must be repeated daily for four to six weeks.
“Just under 50 per cent respond well to the treatment. Our latest study shows that 16 per cent become completely free of depression. And then we must bear in mind that these patients are suffering from depression that is difficult to treat. Many of them may have tried seven to ten different medications without success,” says Robert Bodén, consultant at Uppsala University Hospital and professor of psychiatry at Uppsala University.
Magnetic fields affect brain cell activity
The treatment is a form of transcranial magnetic stimulation called intermittent theta burst stimulation (iTBS). It involves sending magnetic pulses to the patient’s forehead, which induces a weak electric field in the frontal lobe. Depending on the frequency of the pulses, the neurons in the brain can be influenced to make signalling easier or harder.
In depression, it is not only the front part of the brain that is involved. But treating the cells of the frontal lobe is a means of affecting the network that leads deeper into the brain.
“In our studies, we have seen that magnetic stimulation affects how the treated area communicates with other parts of the brain.”
Boden and his team are particularly interested in targeting the anterior cerebral cortex (ACC), an area in the centre of the brain associated with a wide range of brain functions, including emotion regulation.
“The more effectively you can influence the network leading to this area, the greater the effect on depression.”
The brain
Thanks to our brain, we can plan our actions, regulate emotions and solve complex problems. The brain also holds both positive and negative memories. But what happens when it malfunctions?
Teenagers and voice hallucinations
In Bodén’s lab, which is located right next to the clinic, they are seeking not just to understand how magnetic stimulation affects the brain, but also to find new diagnoses to treat. A study is currently underway to investigate whether voice hallucinations can be suppressed by magnetic stimulation. The effects on young people suffering from depression are also being studied.
“Only two drug treatments are available that are recommended specifically for teenagers. This makes it important to find new methods. The study we have underway now shows promising results.”
The plan for next year is to investigate the effect of the treatment on people suffering from eating disorders. This will be done by allowing in-patients to try magnetic stimulation in combination with a conventional treatment programme.
Bodén believes that several psychiatric diagnoses could be treated.
“If you think of the brain as a road network, I believe it could work in cases where diseases have caused traffic jams. But it may not be as effective in cases where the road network is broken, such as in Parkinson’s and Alzheimer’s.”
Focused ultrasound a new treatment for mental illness
A weakness of transcranial magnetic stimulation is that it can only directly stimulate the superficial parts of the brain, just below the skull. Many areas of the brain that can be linked to depression and mental illness are further in. In order to reach deeper, the University Hospital has recently acquired equipment to treat patients with transcranial focused ultrasound.
“Ultrasound waves pass through skull bones and brain tissue to some extent and can reach a focused point deep in the brain. Transcranial ultrasound affects neurons mechanically, much like shaking them back and forth, which changes the electrical signalling.”
The new technology has many potential areas of use. For example, there are theories that patients in a coma who do not wake up although the injury is mild could be awakened by stimulating the thalamus. Another interesting area of the brain that is difficult to access is the nucleus accumbens. This part is thought to play a key role in depression and addiction problems, among other disorders.
“If you go deeper into the brain, into areas such as the nucleus accumbens, the amygdala or the hippocampus, then you have taken in a substantial proportion of psychiatric diagnoses. The ultimate would be to find a way to influence disease awareness. If we knew which area governed that, much of the compulsory care we have today could be eliminated.”
Sandra Gunnarsson
Transcranial magnetic stimulation
Transcranial magnetic stimulation has been a recommended treatment option in Sweden for depression since 2017. There are two variants: standard repetitive transcranial magnetic stimulation (rTMS) and theta burst stimulation (iTBS). iTBS is a newer method that takes just three minutes per session, compared with 37 minutes for rTMS. Both are equally effective, but iTBS has become dominant in Sweden due to the shorter treatment time.