Obsessive-compulsive disorder (OCD) is a neuropsychiatric condition characterized by the presence of persistent intrusive thoughts, images or urges (obsessions) that lead to compulsions, repetitive mental or motor acts, or avoidance behaviors, in order to reduce anxiety. OCD has a lifetime prevalence of 2%-3%. It begins in childhood, puberty or early adult life, and thus affects a critical period in relational and academic development. The standard treatment for OCD combines psychotropic medication – typically serotonin reuptake inhibitors and antipsychotic potentiation – and cognitive behavioral therapy (CBT), mainly exposure with response prevention. However, around 10% of patients continue to present chronic and severe obsessive-compulsive symptoms despite exhausting all available pharmacological strategies and undergoing intensive behavior therapy. In this group of severely disabled OCD patients, for some decades now neurosurgical interventions have been considered as a potential treatment, in spite of the possible risks.
In deep brain stimulation, electrodes are placed in the targeted areas of the brain. The electrodes are connected to by wires to a type of pacemaker device (called an implantable pulse generator) placed under the skin of the chest below the collarbone. Once activated the pulse generator sends continuous electrical pulses to the target areas of the brain. The deep brain stimulation system operates much the same way as a pacemaker for the heart. In fact, deep brain stimulation is referred to as “the pacemaker for the brain”.
Who should consider Deep Brain Stimulation Surgery?
A person must have OCD as their main diagnosis, causing the most distress and functional impairment for at least 5 years. Their symptoms should be very severe; the individual must have had severe OCD symptoms for at least five years despite receiving adequate treatment. There must also be clear evidence that standard therapies were tried fully and correctly. This includes three adequate trials of serotonin reuptake inhibitors, withat least one trial involving clomipramine, as well as two adequate augmentation strategies such as using antipsychotics or adding clomipramine. In addition, the person must have completed at least 20 hours of OCD-specific cognitive–behavioural therapy, particularly exposure and response prevention (ERP). A psychiatric team must independently confirm that all these treatments were adequate and that the OCD remains treatment-resistant. Eligible patients must be between 18 and 75 years of age, be able to give informed consent, and have clear and realistic expectations about the potential benefits and limitations of the surgery.
What are the symptoms of treatment resistant OCD?
People with treatment-resistant OCD have ongoing, severe symptoms of obsessions and compulsions that do not improve despite multiple treatments. They continue to experience intrusive, unwanted thoughts that cause strong anxiety or discomfort, along with repetitive behaviours like washing, checking, counting, or arranging that feel impossible to stop. These symptoms take up a lot of time each day, disrupt work and daily life, and often continue for years. Many people also avoid situations that trigger their fears, and some may struggle with low insight or worsening anxiety and depression.
What symptoms are unlikely to benefit from DBS?
Some OCD symptoms improve less with DBS. People whose main problem is hoarding symptoms usually do not benefit much from DBS. It also works less well for individuals who have very poor insight into their OCD, or who strongly believe their fears are true. DBS may also help less when severe depression, psychosis, or substance use are the dominant issues. People with OCD driven mainly by “just-right” feelings or body sensations (without clear intrusive thoughts) may also have a weaker response.
How are patients chosen for DBS?
We choose patients for DBS very carefully. It is offered only to people who have severe OCD for many years and who have not improved despite trying all standard treatments. This includes multiple medicines at correct doses, adding other medicines, and completing structured OCD-focused therapy (ERP). A psychiatric team reviews the person’s history, confirms that the OCD truly has not responded to treatment, and checks that the person is between the usual age range (18–75)and can give informed consent. Only patients who meet all these criteria are considered for the procedure.
What is the Procedure ?
The DBS surgical procedure usually takes several hours. For most patients, one electrode is placed in each side of the brain. A frame holds your head (skull) during surgery so the electrode can be placed precisely. A small hole is drilled in each side of the skull so Two thin, insulated wires (each with electrodes known as and contacts) are inserted into the brain. The lead implanted in the left side of the brain controls symptoms affecting the right side of the body, and the lead implanted in the right side of the brain controls symptoms on the left side of the body. Each of the two electrode wires is tunnelled through the skin and connected to a pacemaker-like device (called a neurostimulator) that is placed under the skin in the chest.
Is surgery safe?
In general, DBS is a safe procedure. As with any surgery, there are some risks associated with it. Some of the risks of DBS include infection surrounding the device hardware and bleeding in the brain or implant site. Your neurosurgeon will discuss additional risks with you. Studies have shown that the risks are relatively small, but they should be kept in mind when considering DBS. Most side effects are mild and temporary, such as: Weight gain, difficulty finding words, decreased quality of speech and pacemakers or electrode infections
- Surgical complications include brain hemorrhage, brain infection, wrong location(misplacement) of the DBS leads and less than the best location (suboptimal placement) of the leads.
- Hardware complications include movement of the leads, lead failure, failure of any part of the DBS system, pain over the pulse generator device, battery failure, infection around the device & the device breaking through the skin as the thickness of skin & fat layer change as one ages.
- Stimulation-related complications occur in all patients during the device programming stage.
- Some patients notice temporary mood or behaviour changes after DBS, such as anxiety, low mood, irritability, or impulsivity, which can often be adjusted by changing the stimulation settings.Rarely, people may experience memory or thinking changes, or unwanted sensations during stimulation.
What are the benefits one can expect after the Treatment?
Most people who undergo OCD surgery (like DBS or capsulotomy) experience a meaningful reduction in their OCD symptoms. This often includes fewer intrusive thoughts, less anxiety, and a reduced urge to perform rituals. Many patients find they can resume daily activities, work more easily, participate in social life, and feel more in control of their thoughts and behaviour. Improvements are usually gradual, building over weeks to months, and often continue with the help of ongoing therapy and medication adjustments. Although surgery is not a complete cure, many people achieve a 40–60% improvement in symptoms and a better overall quality of life.
What are the advantages of deep-brain stimulation over other surgical treatments available for OCD?
Deep Brain Stimulation (DBS) has many advantages:
- DBS does not cause permanent damage in any part of the brain, unlike capsulotomy which surgically destroy tiny areas of the brain and therefore is permanent and not reversible.
- The electrical stimulation is adjustable and reversible as the person’s disease changes or his or her response to medications change.
- Because DBS is reversible and causes no permanent brain damage, use of innovative not yet available treatment options may be possible. Thalamotomy and pallidotomy result in small, but permanent changes in brain tissue. A person’s potential to benefit from future therapies may be reduced if undergoing these procedures.
- The stimulator can also be turned off at any time if DBS is causing excessive side effects without any long-term consequences.