Deep Brain Stimulation for Treatment-Resistant Depression: Process and Risks

Deep brain stimulation (DBS) for depression is a promising surgical neuromodulation method for resistant cases that do not respond to standard medication and psychotherapy. By placing thin electrodes in specific regions of the brain that regulate mood, abnormal electrical activity is modulated, alleviating the symptoms of major depression. This innovative approach helps patients who have been trapped in a dark state of mind for many years return to daily life and regain their lost quality of life.

In short:

• Deep Brain Stimulation works by sending continuous, mild electrical impulses to specific areas of the brain.
• It is only considered for patients with treatment-resistant depression who have not responded to at least two or more different antidepressant therapies.
• It is meticulously planned by a multidisciplinary council comprising psychiatry, neurology, and neurosurgery specialists.
• Post-surgery, the device settings are gradually optimized over months based on the patient's mood and clinical response.
• Depending on the type of device used, rechargeable batteries can last up to 20-25 years, while non-rechargeable ones last an average of 5 years.

How Does Deep Brain Stimulation Work in Treatment-Resistant Depression?

The application of DBS for major depression fundamentally operates on a system similar to cardiac pacemakers. Depression is not just a simple chemical imbalance; it is also a disruption of electrical communication in the neural networks (neural circuits) that manage mood, motivation, and decision-making. DBS targets these disrupted communication networks by delivering continuous, adjustable, and reversible electrical impulses.

The system consists of three main parts: thin electrodes placed in targeted deep regions of the brain (such as the subcallosal cingulate or medial forebrain bundle), a generator (battery) placed under the skin below the collarbone, and subcutaneous extension cables connecting the two. The generator delivers electrical current to the brain at a programmed frequency and intensity. This current normalises the function of overactive or underactive brain regions causing depression. The effect is usually not immediate; it can take weeks to months for the brain to adapt to the new electrical pattern and for neural networks to reshape.

Who is a Candidate?

DBS for treatment-resistant depression is not a first-line treatment for every depression patient. This method is reserved for the most severe cases where all traditional treatments have been tried and failed. For a patient to be a candidate for DBS, they must first have a confirmed diagnosis of major depressive disorder, and this condition must have persisted continuously or recurred frequently for at least several years.

Candidacy criteria include having used antidepressants from different groups in adequate doses and durations, having completed evidence-based psychotherapy sessions, and often having not responded to other somatic treatments like electroconvulsive therapy (ECT). Furthermore, the patient must be in good physical health to withstand general anaesthesia and neurosurgery. Individuals with active substance abuse, severe dementia, or primary psychotic disorders other than depression are generally not considered suitable candidates. The decision process requires a highly detailed review of the patient's medical history.

Symptoms of Treatment-Resistant Major Depression

Treatment-resistant depression is a profound and persistent state of collapse that brings a person's life to a complete standstill. Patients become unable to enjoy any activities they previously found pleasurable (anhedonia). Getting out of bed in the morning, maintaining personal hygiene, or even keeping up a simple conversation can feel like an insurmountable mountain. Sleep patterns are completely disrupted; the person either sleeps all day or suffers from severe insomnia. Loss of appetite or binge eating episodes are common.

Slowing of cognitive functions is one of the most prominent and frequently overlooked symptoms of treatment-resistant depression. Patients struggle immensely with focusing, making decisions, and remembering the recent past. Sometimes this cognitive slowing is so severe that it might be mistaken for an underlying neurological issue. In such cases, to accurately identify the root of the symptoms, it is crucial to rule out other possible causes such as memory problems and vitamin deficiencies. In the most severe cases, a constant sense of guilt, feelings of worthlessness, and recurrent suicidal thoughts dominate the clinical picture.

Multidisciplinary Approach: How Does the Council Process Work?

Success in DBS treatment depends on selecting the right patient. Therefore, the process is managed not by the decision of a single physician, but by a multidisciplinary council where different specialties come together. At the heart of this council are the Psychiatry, Neurosurgery, and Neurology departments. The process begins with a detailed evaluation of the patient by a psychiatrist. The accuracy of the diagnosis, the reality of treatment resistance, and the patient's expectations are analysed.

Then, neurology and neurosurgery teams step in. Detailed MRI scans are performed to see if the brain structure is suitable for surgery. The patient's mental capacity is measured with neuropsychological tests. In the council meeting, all this data is put on the table. The psychiatrist discusses the patient's mental state, the neurosurgeon discusses the technical feasibility of the surgery, and the neurologist discusses potential neurological risks. When a consensus is reached among all specialists, a transparent conversation about risks, benefits, and long-term expectations is held with the patient and their family to finalise the surgery decision.

The Deep Brain Stimulation Surgery Process and Recovery

DBS surgery is a highly delicate stereotactic surgical procedure that requires advanced technological equipment. The surgery is usually performed in two stages. In the first stage, a special frame is attached to the patient's head, and the brain is mapped with millimetric calculations. While placing the electrodes into the brain, the patient is usually kept awake under local anaesthesia to ensure the correct area is targeted. During this time, the surgical team talks to the patient to test for immediate changes in mood or potential side effects.

In the second stage, the patient is placed under general anaesthesia. The cables of the electrodes placed in the brain are routed under the skin to the neck area, and from there, connected to the generator (battery) placed below the collarbone. After surgery, patients are typically monitored in the intensive care unit for a day and in a regular ward for a few days before being discharged. However, the real treatment process begins after discharge. The device is turned on a few weeks after the surgery. Psychiatrists and neurologists slowly adjust the voltage, frequency, and pulse width of the device over months using a special programmer, based on the patient's responses. While rechargeable batteries are charged weekly by patients at home, non-rechargeable batteries need to be replaced with a minor surgical procedure on average every 5 years.

What Are the Risks?

As with any surgical intervention, DBS for psychiatric disorders carries certain risks and potential complications. Surgical risks include bleeding, infection, or reactions to anaesthesia, which can occur at a rate of 1-2 percent. Because brain tissue is intervened with, there is a very rare risk of stroke; therefore, precise calculations during surgery are of vital importance.

Hardware risks include electrode displacement, cable breakage, or premature battery depletion. In these cases, revision surgeries may be required. Psychiatric risks arise during the device adjustment process. If the electrical stimulation is too high, the patient may temporarily experience hypomania (excessive cheerfulness, hyperactivity, decreased need for sleep), increased anxiety, or restlessness. If the device suddenly turns off or the battery runs out, depression symptoms can return very quickly and severely. Therefore, it is essential for patients to be highly disciplined regarding device maintenance and doctor check-ups.

When to See a Doctor?

During the follow-up of treatment-resistant depression and after DBS surgery, certain symptoms require immediate medical attention. It is vital for the patient and their relatives to know these warning signs. If you experience any of the following situations, you should call 112 emergency services without delay or go to the emergency department of the nearest fully equipped hospital:

• Thoughts of harming yourself or others, suicide plans, or actions.
• Sudden onset of severe redness, swelling, increased warmth, or discharge at the surgical sites (head, neck, or chest), indicating a suspected infection.
• Sudden severe headache, speech impairment, numbness, or loss of strength on one side of the body.
• Inability to charge the battery or receiving warning signals that the device has turned off.
• Sudden, unexplained, very severe emotional collapse or extreme exuberance (mania).

The Process at BHT CLINIC

At BHT CLINIC İstanbul Tema Hastanesi, the DBS evaluation process for treatment-resistant depression patients is carried out through the coordinated work of our expert psychiatry, neurology, and neurosurgery teams. When you apply to our hospital, your past medical records, the medications you use, and the treatments you have received previously are first examined in detail. Therefore, bringing all your old epicrisis reports and medication lists with you to the first consultation will speed up the process.

Our multidisciplinary council meets regularly to determine the safest and most effective treatment path for you. If a surgery decision is made, your procedure is performed in our advanced technology operating rooms with JCI accreditation. Post-surgery device adjustments and psychiatric follow-ups are maintained within a long-term plan. For unexpected situations, our 24/7 emergency service is always by your side. To start the evaluation process, you can easily schedule a consultation with our specialists via our appointment page.

Frequently Asked Questions

Is deep brain stimulation a definitive cure for psychiatric diseases?

DBS is not a magic wand that completely eliminates treatment-resistant depression. Its goal is to reduce the severity of the disease and enable the person to regain their daily life functions. Although a very significant increase in quality of life is achieved in many patients, the response rate to the treatment varies from person to person.

Is pain felt during surgery?

Local anaesthesia is applied to the patient during the opening of the skull and the placement of the electrodes. Since the brain tissue itself does not have pain receptors, no pain or ache is felt while the electrodes advance within the brain. There may only be a slight feeling of pressure.

Are antidepressants stopped after deep brain stimulation?

Antidepressant medications are generally not stopped immediately after surgery. As the effect of the device settles over months, medication doses can be gradually reduced under the supervision of a psychiatrist. While some patients can stop medications completely, others continue treatment with lower doses.

What happens when the battery runs out?

When the lifespan of non-rechargeable batteries expires or the battery life of rechargeable ones is depleted, the device stops delivering electrical impulses. In this case, depression symptoms can return within a short time. Battery replacement is a short and simple surgical procedure where only the generator in the chest area is replaced, without any intervention to the brain.

Does deep brain stimulation prevent MRI scans?

Many new-generation DBS devices are MRI-compatible under certain conditions. However, the device may need to be put into a special mode or turned off before an MRI scan. It is absolutely necessary to inform the radiologist and the physician monitoring your DBS device before any MRI scan.

This article is for informational purposes only; please consult your physician for diagnosis and treatment.