Psychosurgery

The Biological Approach to Treatment

As the name suggests, the biological approach to treatment only considers the biological factors that can contribute to mental illness and aims to tackle these at their root, thereby hoping to treat the illness under question. This is based on three assumptions, which we'll briefly discuss below.

• Evolutionary Influences - Natural selection suggests that species that survive the stage of sexual maturity will produce offspring that possess their traits. In contrast, those who do not survive this stage will not pass any genetic material onto their offspring. With the passing of each generation, different mutations occur, resulting in the offspring being born with 'successful' genes from their ancestors.

• Localisation of Brain Function - We know that our brain is divided into different sections, each of which has its own specific function. These functions work together to allow us to understand, think, feel and behave. So, what does 'localisation of brain function' mean, and how is it different? In addition to suggesting that the brain has different sections responsible for different functions, it suggests that if one of these sections of the brain were to become damaged, then the function associated with it would be damaged too.

• Neurotransmitters - Our nervous system is made up of tiny cells called neurons. Neurons must communicate with each other to allow the body and mind to function. Neurotransmitters are what send these signals. These have two effects - excitatory when there is increased activity and inhibitory when there is decreased activity. Irregular neurotransmitter levels have been associated with specific mental illnesses.

Psychosurgery: Meaning

Psychosurgery involves brain surgery to treat mental disorders such as obsessive-compulsive disorder (OCD), schizophrenia and depression. It is a collaboration between psychiatrists and neurosurgeons.

Psychosurgery aims to remove the connections in the brain areas responsible for symptoms and reflects the medical model of mental health, which assumes that mental illness has physical causes. As a result, there are both benefits of psychosurgery and psychosurgery side effects.

Figure 1: Psychosurgery is a biological intervention that is not often used due to how invasive the procedure is, flaticon.com.

Types of Psychosurgery

Let's take a look at some common types of psychosurgery used today. Modern psychosurgery usually targets the brain's limbic system (which controls emotions) and uses heat to burn away small brain tissue in brain regions.

The common procedures are anterior capsulotomy, anterior cingulotomy, subcaudal tractotomy, and limbic leucotomy. Another type of procedure is deep brain stimulation; this procedure does not remove brain tissue but uses electrical pulses to simulate different brain areas.

Anterior Capsulotomy Psychosurgery

An anterior capsulotomy is most commonly used to treat OCD. Radiofrequency heat lesions or gamma radiation are used to burn away connections and create a lesion in the anterior portion of the inner brain capsule.

The anterior capsulotomy is effective in approximately 50% of patients who show a reduction in OCD symptoms (Brown et al., 2016¹; Rück et al., 2008²). The possible side effects of this procedure are weight gain, problems with executive function, apathy and disinhibition issues (Rück et al., 2008²).

Subcaudate Tractotomy Psychosurgery

Subcaudate tractotomy is used to treat anxiety, depression, and OCD. The procedure targets and destroys a small portion of the white matter tracts (white matter consists of axons that transmit signals in the brain) under and in front of the caudate nucleus (responsible for goal-directed action).

Bridges et al. (1994)³ conducted a study in which 40–60% of patients who underwent subcaudal tractotomy could potentially live normal lives afterwards if they continued to take medication.

Limbic Leucotomy Psychosurgery

Limbic leucotomy is used as an intervention for OCD and depression. It is a combination of anterior cingulotomy and subcaudal tractotomy. It is usually used when a patient does not respond to cingulotomy. Lai et al. (2020) performed a systematic review and meta-analysis and found that the response rate for limbal leucotomy was 47%.⁴

Side effects of limbic leucotomy psychosurgery are short-term and include transient hallucinations, amnesia and mania (Sinha et al., 2015).⁵

Deep Brain Stimulation

Deep brain stimulation is a procedure that uses electrical impulses to simulate different areas of the brain. These electrical impulses regulate abnormal brain activity and balance chemical imbalances. This stimulation is done with a neurostimulator device, which sends electrical impulses to electrodes placed in the brain. The neurostimulator is placed in the person's chest and connected to the electrodes via wires.

Deep brain stimulation can be used to treat movement disorders such as the symptoms of Parkinson's disease. It is also used to treat OCD.

A meta-analysis by Alonso et al. (2015)⁶ found that patients' scores on the Yale-Brown Obsessive-Compulsive Scale improved by 45.1%, and 60% of patients responded to treatment.

Psychosurgery for Depression: Anterior Cingulotomy Psychosurgery

Anterior cingulotomy is usually used to treat obsessive-compulsive disorder (OCD) and sometimes as a treatment for depression. The procedure is performed with a laser system or thermal energy to create a tiny lesion in the anterior cingulate gyrus.

Sheth et al. (2013)⁷ found at the first follow-up (average 10.7 months after the procedure) that 35% of patients had a complete response to the treatment of OCD symptoms. At the final follow-up, depression severity had also decreased in 17% of patients. The possible side effects associated with this procedure are headaches, nausea, vomiting and seizures (Agarwal et al., 2016)⁸.

Psychosurgery: Evaluation

Let's now evaluate the process of psychosurgery and discuss its strengths, weaknesses and possible side effects.

Benefits of Psychosurgery

In the same way we, as individuals, have evolved over the years, methods of treatment have as well; psychosurgery is no different. The strengths of psychosurgery have mainly been observed in the modern-day treatment method.

Even though there is now a rise and advancement in psychotherapy methods, many individuals don't respond to these. For those with treatment-resistant OCD, anterior cingulotomy can be effective. Sheth et al. (2013)⁷ found that up to 70% patients that suffered from treatment-resistant OCD benefitted in some way from the anterior cingulotomy procedure.

A study conducted in 1975 examined 208 patients who underwent a subcaudate tractotomy; it was found that almost two-thirds of the patients that suffered from anxiety or depression showed improvement, as did 50% of patients diagnosed with OCD.⁹

Further, research on limbic leucotomy psychosurgery has shown a 73% improvement rate in individuals suffering from major depressive disorder (MDD) and OCD who initially underwent the anterior cingulotomy procedure but did not respond.¹⁰

Weaknesses of Psychosurgery

We have discussed the success rates of psychosurgery in patients with treatment-resistant mental illnesses and seen that it does, in fact, improve symptoms. However, as with any treatment method, it does not come without its own weaknesses, the most common of which are the side effects associated with these procedures.

Surgery is complicated in any area of the body, but more so in the brain. A complication could arise that can be dealt with at the moment, but whether or not it will have a lasting impact on the patient can only be found once the patient is awake and responsive.

Psychosurgery does not account for other factors, such as childhood events or environmental factors that may contribute to mental health. Therefore, the intervention can be argued as reductionist.

In addition, psychodynamic psychologists argue that biological interventions simply mask the problem instead of getting rid of the root problem; in theory, it's argued this makes relapse more likely.

Let's look at some of the side effects that can arise from psychosurgery and, more specifically, deep brain stimulation.

Psychosurgery Side Effects

Let's look at some of the side effects that can arise from psychosurgery and deep brain stimulation.

The different types of psychosurgery are associated with the following side effects.

Similarly, there are serious side effects associated with deep brain stimulation.

Keeping the complex nature of this procedure in mind, the recovery process is a slow and lengthy one - the effects of the surgery are mainly seen up to 12 months after it was originally performed.