According to the statistics of the World Health Organization, the number of people in the world suffering from depression is increasing every year. For example, if in the early 90s in developed countries up to 20% of the population sought medical help in connection with this diagnosis, then by the end of the 90s this figure had increased to 25%. In Russia, this figure reaches 65%.
The most common treatments for depressive disorders are the following therapies:
- medication (antidepressants);
- psychotherapy (psychiatric supervision);
- hardware and restorative (magnetic stimulation, biofeedback, light therapy and other types);
- supporting;
- relapse prevention.
Any of these areas gives an effective result only when used in combination with other methods of treatment.
The use of antidepressants leads to the desired result only in 60% -70% of cases and must be combined with psychotherapy. In addition, potent drugs have a large number of side effects.
As an alternative to medical treatment, other directions are becoming more widespread. Among the hardware methods, the leading role is played by the use of transcranial magnetic stimulation (TMS) in combination with other rehabilitation procedures.
TMS as an antidepressant
A lot of research is devoted to the question of which areas of the brain stimulation is more optimal.
For example, initially, to achieve an antidepressant result, the coil was placed in the vertex projection (that is, in the region of the crown). But based on data from other studies (functional nuclear magnetic ( fNMR ), electroconvulsive , positron emission tomography (PET)) scientists suggested that stimulation of the prefrontal cortex would have a more pronounced effect. Interesting results were obtained during the experiments.
TMS of the right prefrontal cortex in such patients with depression led to an increase in anxiety. Stimulation of the left similar area in 6 patients with drug-resistant depression after 5 days led to positive dynamics and a decrease by 26% on the Hamilton Depression Scale. Rating Scale -HDRS). The results obtained are higher than with the use of drug therapy and even ECT.
It has also been shown that the use of serotonin inhibitors in combination with high-frequency magnetic stimulation ( vTMS ) in patients with depression causes a faster and more lasting effect than therapy without magnetic stimulation. In depressed patients, dexamethasone suppression tests may change from positive to negative with rhythmic TMS ( rTMS ) at a frequency of 10 Hz and an induction of 100% of motor threshold
However, we must not forget that the interpretation of the data obtained sometimes causes certain difficulties, since for this it is necessary to perform double-blind studies with randomization, the use of false effects, which is not always possible with patients.
Comparison of TMS and ECT
Studies conducted in two groups (40 patients with depression) showed that in patients without psychosis, the effectiveness of vTMS of the left prefrontal cortex for 4 weeks and ECT is approximately the same. Patients with psychosis have a higher clinical benefit with ECT.
Other researchers have also come to
similar results. Positive clinical manifestations in TMS (10-20 daily sessions at a frequency of 10 per second) did not differ significantly from the data in the group where ECT was performed.
It can be assumed that the mechanisms of TMS and ECT are somewhat similar, and positive clinical results allow us to consider the possibility of replacing ECT with a more gentle vTMS over time . With magnetic stimulation, there is no need for anesthesia, and side effects such as epileptic seizures and retrograde amnesia are much less or completely absent.
Schizophrenia and manic depressive disorder
In the early 2000s, studies began on the therapeutic use of TMS for patients with depression associated with schizophrenia. There are reports of a reduction in auditory hallucinations in patients with rTMS in the projection of the left temporal region. It has been shown that it is possible to reduce anxiety in schizophrenia after exposure to rTMS , to reduce negativism with rTMS in the left prefrontal area,
as well as other data that allow you to look optimistically at this direction of treatment.
Studies in patients with acute manic manifestations have shown that vTMS in the projection of the right prefrontal region reduces manic symptoms. The data obtained suggest that in manic states, tMS in the right prefrontal region is effective, and in order to obtain an antidepressant effect , it is desirable to apply tMS in the projection of the left region.
There are reports of a positive therapeutic effect with tMS at a frequency of 20 Hz (80% of the motor threshold) in the projection of the right frontal region in 12 right-handed patients with obsessive- compulsive states, while exposure in the projection of the left prefrontal and occipital cortex was not effective.
Further research
With the development of technology and the improvement of therapeutic methods, there is a need to conduct a deeper study of the methodology to accurately determine the indications, contraindications for the use of TMS, as well as new possibilities for the application of the method and more accurate prediction.
In 2015, a US study was conducted that proved the effectiveness of TMS for patients with major depressive disorder (MDD). The experiment consisted of several stages and consisted of examining
patients who were exposed to TMS, when a clinical effect was detected, took antidepressants, and then were observed for six months with an assessment of the persistence of the treatment effect.
Stimulation parameters: motor threshold 120% (MT), frequency 10 Hz, exposure duration 4 sec, interval 26 sec and a total of 75 sets per session, which amounted to a total of 3000 impulses for 37.5 minutes.
The results showed a high effect of the TMS method in the group compared with the placebo control group on the Montgomery -Asberg scale . Analysis of the effectiveness of treatment in patients who did not respond to drug therapy showed even better results.
Decreased suicidal tendencies
Also in America (Toronto), a study was conducted that proved a sharp decrease in thoughts about suicide in the control group after exposure to rTMS on the Hamilton scale. The experiment involved 156 people suffering from depression with no result after 2 courses of drug treatment. The stimulation of the dorsolateral region of the prefrontal cortex of both cerebral hemispheres showed the greatest effect.
Application of high frequency rTMS
To date, 2 methods of using rTMS as an antidepressant are used in world practice: with a frequency of more than 1 Hz – to stimulate the left frontal cortex, and with a frequency of less than 1 Hz – to stimulate the right side.
The most widely used method is high-frequency rTMS . It is used for the following indications:
- episodic cases of depression – as an independent treatment;
- depression of moderate and severe severity – in combination with drug and psychotherapeutic assistance;
- lack of a positive result of previous courses of therapy;
- high risk associated with side effects of medications or complete contraindications to them;
- the activity of the patient, requiring increased concentration of attention;
- chronic pain;
- the wishes of the patient.
TMS is used most often as an active agent that relieves an acute condition. After the end of the course of magnetic stimulation, maintenance drug therapy is prescribed.