Experts See Mind’s Voices in New Light

Auditory hallucinations are a hallmark of schizophrenia: 50 percent to 75 percent of the 2.8 million Americans who suffer from the illness hear voices that are not there. Like John, whose schizophrenia was diagnosed in 1981 and who spoke on the condition that he not be identified, many people with schizophrenia spend years pursued by verbal tormentors as relentless as the furies of Greek mythology. Suicide is sometimes the result, death seeming the only escape from unending harassment.

Yet psychiatrists who study schizophrenia have traditionally shown little interest in the voices their patients hear, often dismissing them as simply a byproduct of the illness, “crazy talk” not worthy of study.

Recently, however, a small group of scientists has begun studying auditory hallucinations more intensively. Aided by new brain imaging techniques, they have begun tracking such hallucinations back to abnormalities in the brain, finding that certain brain regions “light up” on brain scans when patients are actively hallucinating. And the experts are listening far more carefully to what patients say about their hallucinatory experiences.

(…) What everyone who studies hallucinations agrees on is that schizophrenic patients misperceive signals generated inside the brain. But scientists are still debating what is being misinterpreted and how this occurs. NY Times

Two theories are highlighted in the article as if they are diametrically opposed. Some mental health researchers think hallucinations represent a misconstrual of inner dialogue as if it were outer. (In my own psychiatric work, I focus on the breakdown in one sort of schizophrenia of mechanisms which maintain the boundaries between the self and the world. Among other things, this results in a confusion between the inner and the outer, self and not-self.) Other researchers think that cerebral tissue loss in schizophrenia results in a closer neural connection between the speech production and speech reception centers in the cerebral cortex. This is the cause, they feel, of there being no barriers to internal dialogue being experienced as if it were externally perceived speech. But, if we get beyond the artificial split between the neural and the psychological, are these really as distinct as they are made out to be?

The article also makes much of the success of transcranial magnetic stimulation in treating refractory hallucinatory symptoms.

In the treatment, an electromagnetic coil shaped like a Figure 8 is held to the patient’s head. The coil produces a quarter-size magnetic field that is then rapidly turned on and off, inducing an electrical field in the cerebral cortex’s gray matter.

Scientists do not know exactly how the treatment works, but they believe it dampens the reactivity of neurons, an effect that is then passed on to other connected brain regions.

Unlike electroshock therapy, long used for severe depression, transcranial magnetic stimulation does not induce seizures at the levels used in the studies and has a far more selective effect on the brain. Nor does the treatment appear to have the serious side effects, like memory loss, of electroshock therapy.

I think the verdict is still out on TMS. The new research about the meaning of hallucinations has far more interesting implications than simply rationalizing the use of another technology that, while appearing more subtle than others in the history of psychiatry, follows in a long tradition of disrupting and ablating mental activity because, imperfectly understood, it is distressing to the patient or — far more troubling — to the treaters.