TMS for Depression
Depression poses treatment challenges, but Transcranial Magnetic Stimulation (TMS) offers promise for treatment-resistant patients by targeting specific brain regions.
Combining TMS with antidepressants and psychotherapy enhances treatment outcomes, showing potential for personalised symptom reduction and management.
Advanced TMS systems like the H-coil provide deeper stimulation and superior benefits, offering the best results available to people with treatment-resistant depression.
Introduction
Depression is a widespread mental health disorder that affects a significant portion of the population. Conventional approaches to depression treatment, such as medication and psychotherapy, often come with limitations, including variable effectiveness and undesirable side effects. In recent years, transcranial magnetic stimulation (TMS) has emerged as a promising intervention for treatment-resistant depression. By targeting specific regions of the brain, particularly the dorsolateral prefrontal cortex (DLPFC), TMS offers a non-invasive method to regulate neural activity and reduce depressive symptoms. Combining TMS with other treatments, such as SSRIs or cognitive-behavioural therapy (CBT), shows potential for enhancing treatment outcomes and providing personalised management strategies.
Depression
Depression, also known as clinical depression or major depressive disorder, is a common psychiatric condition with an estimated lifetime prevalence of 10% of the general population [1], meaning that roughly 1 in 10 people will experience depression during their lives. Some researchers estimate that number to be as high as 20% of the general population [2]. The most common symptoms of this condition are depressed mood or anhedonia (loss or lack of interest or pleasure), changes in appetite or weight, sleep disturbances such as insomnia or hypersomnia, fatigue or loss of energy, reduced cognitive ability and attention span, and suicidal thoughts. In order for a diagnosis of clinical depression to be made, patients must display at least five of these symptoms within a 2-week period [3].
Depression is a condition that affects people of all ages, genders and demographic groups, although it often begins presenting in adolescence or early adulthood [4]. There are a number of factors that can increase a person’s risk of developing clinical depression. These risk factors include family history of depression or mental illness, physical health problems, chronic medical conditions, bereavement, trauma, and stress, to name a few [5].
Treatment of depression
To treat clinical depression, patients are often prescribed a combination of antidepressant medication and psychotherapy, with the medication being used to reduce symptoms and the psychotherapy being used as a tool to explore the root causes of the condition and teach patients skills and coping methods to deal with potential stressors and triggers [6]. However, this approach does not work for everyone. Psychotherapy is often a long, arduous and expensive process, which many patients find overwhelming and difficult to commit to [7]. Medication, while having the potential to reduce depressive symptoms within a relatively short amount of time, can often cause unwanted side effects such as fatigue, nausea, sleep disturbance, loss of libido, weight-gain, and addiction. Furthermore, recent research has found that 20-60% of psychiatric patients are treatment resistant, meaning that their prescribed medication will have little-to-no effect and may require alternative treatments [8].
TMS treatment of depression
TMS is a noninvasive treatment that uses magnetic fields to stimulate nerve cells in the brain to improve symptoms of several psychiatric disorders. It is generally only prescribed to treatment-resistant patients who have already tried other methods such as medication or psychotherapy. It works by delivering electromagnetic pulses to specific areas of the brain, which can adjust brain activity and improve symptoms. In patients with clinical depression, Functional magnetic resonance imaging (fMRI) studies have found an underactivity in a part of the brain called the dorsolateral prefrontal cortex (DLPFC) [9]. TMS treatment of depression involves the stimulation of the DLPFC in order to increase activity in this area of the brain and reduce symptoms.
Research has shown that high-frequency TMS over the left-DLPFC and low-frequency TMS over the right-DLPFC are associated with statistically and clinically significant reductions in symptoms of depression, and were both roughly 3 times more effective than sham treatment [10]. These findings are supported in the wider literature, with one study finding that high-frequency TMS over the DLPFC had a significantly higher response rate than sham treatment (38.4% vs. 21.4%), as well as a significantly higher remission rate (32.6% vs. 14.6%) [11]. Similarly, a systematic review of 63 studies found that active TMS over the DLPFC produced a larger reduction in symptoms than sham TMS treatment (45.21% vs. 25.04%) [12].
TMS and medication for depression
TMS has been consistently shown, throughout the literature, to have statistically significant antidepressant effects for patients with treatment-resistant depression. There have also been a number of studies comparing the efficacy of this treatment with common antidepressant medications such as selective serotonin reuptake inhibitors (SSRIs).One For example, one study assessed the remission rates of depressed patients treated with a combination of high-frequency TMS and low-dose SSRIs against those treated with sham TMS and low-dose SSRIs. The findings showed that 35.3% of patients treated with active TMS and SSRIs achieved clinical remission, compared with 0% in the sham group [13]. Another study found that, when combined with antidepressant medication, TMS produced a response rate of 70.6% and a remission rate of 41.2% [14]. These findings indicate that not only is TMS an effective treatment for people with clinical depression, but that when combined with traditional antidepressant medication it can significantly enhance results.
TMS and psychotherapy for depression
It can be difficult to compare and contrast the efficacy of TMS with traditional forms of psychotherapy such as CBT. There are, however, several studies that look at the response and remission rates in patients who receive clinical TMS treatment combined with psychotherapy, rather than psychotherapy alone. For example, a recent meta-analysis of 27 found that TMS combined with psychological interventions such as CBT and mindfulness, was significantly more effective at reducing psychiatric symptoms than psychological interventions alone [15]. These findings are supported by another recent analysis, which also highlighted the faster response rates of patients treated with TMS combined with psychotherapy than of those treated with psychotherapy alone [16]. These findings suggest that, when combined with TMS, the response and remission rates of psychological interventions such as CBT can be improved upon and even accelerated.
dTMS vs. rTMS for depression
While TMS, in general, has been shown to be a safe and effective treatment for patients with clinical depression, there are a number of different TMS systems available to patients, which use different treatment protocols and magnetic coils to provide stimulation. The most commonly used coil is known as the Figure-8 (F8) coil, which most TMS manufacturers use. However, there is a more advanced coil called the Hesed-coil (H-coil). The H-coil was patented by Brainsway and is used exclusively in Brainsway machines. The difference between these 2 coils is that the H-coil is able to stimulate deeper regions of the brain than the F8 coil, which is why H-coil TMS is often referred to as Deep TMS (dTMS). A recent meta-analysis and review of 19 studies found that H-coil TMS produced larger response and remission rates in patients with clinical depression than F8-coil TMS, with comparable rates of side effects [17]. These findings are corroborated by an independent study showing that H-coil treatment reduced symptoms of depression in 59% of patients compared with 41% for F8-coil treatment [18]. We can conclude from this research that while both forms of TMS are effective at treating clinical depression, the H-coil produces more significant benefits.
Conclusion
In conclusion, the research presented in this article shows that TMS offers a promising intervention for treatment-resistant depression. Studies demonstrate that TMS, particularly high-frequency stimulation over the left-DLPFC, effectively reduces depressive symptoms, with enhanced efficacy when combined with antidepressant medication. Integration of TMS with psychotherapy, such as cognitive-behavioural therapy (CBT), shows improved outcomes, including faster response rates. Advancements like the H-coil for deep TMS expand treatment options, indicating superior response and remission rates. TMS presents a valuable addition to depression treatment, offering personalised and effective management approaches.
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