Characterized by behavioral, cognitive, and mood disturbances, schizophrenia is difficult to treat. One reason for this is that every individual has differing symptoms and responds to treatments differently.
One of the most disturbing symptoms for people with schizophrenia and those around them are hallucinations. These can be visual or tactile hallucinations, but most frequently, they are auditory - often in the form of voices.
Hearing voices is so common in schizophrenia that it is often used as a "principal indicator" of a schizophrenia diagnosis.
The origin of schizophrenia's voices
The voices, or auditory verbal hallucinations (AVHs), heard by people with schizophrenia vary substantially. AVHs can be threatening, confusing, and difficult to distinguish from reality.
There may be one voice, or there may be competing voices. The voices might constantly criticize the individual, or they may appear to be the voice of a dead relative or friend.
And because AVHs come from within the individual's mind, they can be incredibly convincing. Also, because there is no escape from the internal dialogue, they can be exhausting.
Recently, a team of researchers - led by Prof. Sonia Dollfus from the University of Caen in France - embarked on a project to understand and potentially reduce the frequency of AVHs. They used a technique called transcranial magnetic stimulation (TMS).
TMS is a noninvasive technique that uses magnets to influence brain activity. It is a relatively safe procedure that has been used to successfully treat a number of conditions, including depression that does not respond to medication.
TMS involves sending pulses of magnetic energy into the brain, in the same quantities as those used during an MRI scan. If the pulses are passed through the skull in quick succession, it is referred to as repetitive TMS (rTMS), which produces longer-term changes in brain activity.
Although earlier studies have looked at rTMS as a potential way to influence AVHs, so far, findings have been inconclusive. This most recent project, for the first time, specifically investigated high-frequency rTMS in a controlled trial.
The team was particularly interested in a subsection of the left temporal lobe (the ascending branch of the left lateral sulcus and the left superior temporal sulcus), which is involved in language and has been previously identified as the potential home of AVHs.
Using TMS against AVHs
In total, 59 schizophrenia patients were involved in the trial. Each participant was interviewed prior to the study to ascertain the level of AVHs they normally experience, and they were assessed using the standardized Auditory Hallucinations Rating Scale.
Twenty-six of them received high-frequency rTMS, and the remainder received a sham procedure that mimicked TMS. The first group was given a series of high-frequency (20 Hertz) magnetic pulses twice per day for 2 days. After 2 weeks, the team re-evaluated the participants.
An impressive 34.6 percent of those receiving rTMS had a significant reduction in AVHs, compared with 9.1 percent undergoing the sham procedure.
"This is the first controlled trial to show an improvement in these patients by targeting a specific area of the brain and using high-frequency TMS."
Prof. Sonia Dollfus
The results were presented at the ECNP conference - held in Paris, France - and will be published at a later date in Schizophrenia Bulletin: The Journal of Psychoses and Related Disorders.
As Prof. Dollfus explains, the significant conclusions from this study are twofold. She said, "[F]irstly, it seems that we now can say with some certainty that we have found a specific anatomical area of the brain associated with auditory verbal hallucinations in schizophrenia."
"Secondly," she said, "we have shown that treatment with high-frequency TMS makes a difference to at least some sufferers."
This study builds on earlier research into the specific parts of the brain responsible for hearing voices. It also produces good evidence that TMS may be useful in reducing this most disruptive symptom.
While there will need to be more research to ascertain what types of stimulation will be most effective, what course duration is best, and which patients are most likely to respond well, the results are certainly encouraging.