Deep brain stimulation proven to be effective for the treatment of treatment-resistant depression

A new study has successfully demonstrated the effectiveness of deep brain stimulation for treatment-resistant depression.

Written by Edward Gould-Brown

Treatment-resistant depression (TRD) is a relatively common occurrence in clinical practice, with up to 50% to 60% [1] of patients not achieving sufficient symptom improvements after several types of treatment for depression is tested. Recently, the effectiveness of deep brain stimulation (DBS) as a treatment for disorders such as Parkinson’s disease has led researchers to investigate whether this treatment could also work for psychiatric conditions such as TRD.

DBS involves a neurosurgical procedure implanting a medical device called a neurostimulator within certain areas of the brain. The neurostimulator sends out electrical impulses through electrodes, which has been shown [2] to be beneficial for the regulation of otherwise treatment-resistant movement and affective disorders, such as chronic pain and Parkinson's disease-related tremors.?

The new study [3], supported by the U.S National Institutes of Health, investigated whether DBS could be used to regulate mood and respond to stimulation. Researchers adapted a technique known as intracranial electroencephalography (EEG), an electrode brain activity monitoring system often used in the treatment of epilepsy, to analyse the brain networks of an individual with TRD.

Innovation in the treatment of treatment-resistant depression

The first and only participant was an individual with a history of severe TRD. For this patient, the researchers used stereo-EEG to analyse brain activity while at the same time implanting DBS leads in certain regions of the brain thought to be relevant to TRD.

After implanting the leads and electrodes, the patient was monitored and received electrical stimulation whilst carrying out specific behavioural tasks and engaging in unstructured behaviour. The resulting data enabled the research team to generate personalised stimulation parameters for the patient.

In the eight-month outpatient portion of the trial, this personalised stimulation parameters were used to determine the amount of stimulation the patient received from the implanted electrodes. The patient reported steady improvements in mood, concentration, and motivation during this time. Overall, DBS led to a remission of symptoms and a dramatic improvement in the patient's quality of life.

Once that was concluded, the researchers started a blinded portion of the trial, in which they reduced stimulation at times unknown to the patient. This was done to prove that the DBS was reducing symptoms rather than a placebo effect. It was found that the patient's symptoms worsened during the withdrawal phase and improved once stimulation was restarted, confirming that the improvements were a result of the device.

Despite the clear limitations of a single-patient study, the research team are confident that the conclusions of their study have implications for the future treatment of TRD and other psychiatric conditions; they wrote:

'Our initial results demonstrate the feasibility of this novel platform for personalised DBS. We propose that this approach if consistently demonstrated safe and effective, can be used to develop and improve surgical neuromodulation for a vast array of neurologic and psychiatric disorders.'

References

[1]https://pubmed.ncbi.nlm.nih.gov/12706951/

[2] https://www.nature.com/articles/nrn2196

[3] https://www.biologicalpsychiatryjournal.com/article/S0006-3223(21)01747-9/fulltext