Strong Magnetic Fields Aid Severe Depression: New Therapy Has Few Side-effects

For severe depression, electro-shock therapy is nowadays the last hope. However, it can impair memory for weeks after therapy. A less aggressive alternative seems to be provided by what is known as "transcranial magnetic stimulation". This is the conclusion arrived at by doctors and psychologists of the Bonn University Clinic in an article which has just appeared in the British Journal of Psychiatry (vol. 186 [2005], pp. 410-416).

Nowadays depression is seen as amenable to treatment: with psychotherapy or medication most patients affected can be assisted out of their depressive phase. About five per cent of all patients, however, fall into such profound depression that they do not respond to these methods. Because depression is one of the most frequent psychological diseases – every sixth person suffers from it at least once in their lives – this affects a large number of people.

In these cases electro-shock therapy is one option. This involves the patient being anaesthetised. Then the doctors pass electrical impulses through the patient's head via two electrodes, thereby triggering an epileptic spasm. This changes the cerebral chemistry in the area of the forehead, a region which, among other things, regulates the emotions and steers the psycho-motor reflexes.

Effective therapy – bad image

One in two patients who previously did not respond to other therapies improve after a series of therapy to the extent that therapy can be continued by using medication or psychotherapy. 'In the severest cases of depression electro-shock therapy is nowadays still an important therapeutic option,' the head of the Bonn Psychiatric Clinic, Professor Wolfgang Maier, emphasises. Despite this, the public image of this method has long been very negative – not least due to the movie classic 'One Flew Over the Cuckoo's Nest'. In the film the inmate of a psychiatric clinic (played by Jack Nicholson) is subjected to electro-shock to curb his rebellious behaviour.

The type of electro-shock now used is regarded as a form of therapy which is well tolerated by patients. However, the therapy may impair memory even several weeks later. 'As a rule, this impairment of memory does gradually recede, but understandably it is often experienced by patients as annoying,' Bonn lecturer Dr. Michael Wagner says. The reason is that the flow of electricity is not precise enough, also hitting the hippocampus, our brain's 'memory centre'.

This is why recently a different therapy has come to the fore which has few side-effects: in 'transcranial magnetic stimulation' (TMS) the doctors place a coil on the patient's forehead. For several minutes this produces a strong pulsating magnetic field which in turn produces a flow of electrical current. However, this is so weak that it does not trigger an epileptic attack. The patient remains fully conscious during the treatment.

The Bonn researchers have treated a total of 30 patients suffering from severe depression either with electro-shock or magnetic stimulation. Both methods were roughly equally effective: every second patient experienced a marked alleviation of their depression a week after their stint of therapy. 'Admittedly, the division of the groups was not made on a random basis, which reduces the reliability of the findings,' Dr. Wagner warns. 'The number of patients taking part is also too small for us to draw final conclusions about the effectiveness.' However, other studies also confirm that the effect of magnetic stimulation is to improve the patient's mood.

Memory unimpaired by magnetic stimulation

The patients who had been treated with magnetic stimulation later did as well as or even better than before therapy. By contrast, the patients taking part in electro-shock suffered memory loss, psychologist Svenja Schulze-Rauschenbach confirmed. Even so, magnetic stimulation is not a miracle cure, since, like electro-shock, it is not a lasting cure for depression. The patients still have to continue to be treated afterwards with other methods. 'TMS is just a new therapeutic tool which can't help in all cases of depression,' adds Michael Wagner, cautioning against excessively high expectations.

There are only a few institutions in Germany where the effects of this relatively new therapy for severe depression are being investigated. However, new instruments are in the offing which could be even more effective. The magnetic field which they produce is so strong that it can trigger an epileptic spasm. Yet unlike with electro-shock the flow of current in TMS remains restricted to the area of the brain which is responsible for mood – the hippocampus is not affected. Dr. Wagner says, 'We are therefore hoping that this will be an additional very effective method without undesirable side-effects.'

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