Using Transcranial Magnetic Stimulation (TMS) to Treat Obsessive Compulsive Disorder (OCD)
1. What is OCD?
1.1. Definition
1.1.1. Obsessive Compulsive Disorder (OCD) is an anxiety disorder marked byintrusive and/or uncontrollable or recurring thoughts (obsessions), repetitive and excessive behaviors (compulsions), or both. Symptoms may begin to present at any time, though late childhood-young adulthood is the most common age range.
1.2. Subtypes of OCD
1.2.1. Harm OCD: Centers around intrsuive thoughts about harming oneself or others.
1.2.2. Contamination OCD: Centers around intrusive thoughts about germs, dirt, or other substances.
1.2.3. Relationship OCD: Centers around intrusive thoughts about intimate relationships, which often does affect said relationships.
1.2.4. Existential OCD: Centers around intrusive thoughts about one's purpose in life, meaning, and the reality of existence.
1.2.5. Religious OCD: Centers around intrusive thoughts around violating religious, moral, or ethical beliefs.
1.2.5.1. https://www.treatmyocd.com/blog/a-quick-guide-to-some-common-ocd-subtypes?utm_source=google&utm_medium=cpc&utm_campaign=NOCD_PM_US&gad_source=1&gad_campaignid=14264737132&gbraid=0AAAAADEWRhatSxvnWQaNfdZHvmOkSgJmW
1.2.6. 'Just Right' OCD: Centers around an individual's need to have symmetry/symmetrical sensations on both sides of the body.
1.2.7. Meta OCD: Centers around intrusive thoughts about OCD itself, the indivudal often believing that they are 'faking' the disorder or obsessing over whether or not treatments have been effective.
1.2.8. Body-Focused Repetitive Behavior (BFRB) Disorders: Trichotillomania (Hair-pulling disorder) and Dermatillomania (Skin-picking disorder) are both disorders which have a heavy correlation with OCD, and revolve around the repetitive pulling/picking of the hair or skin.
2. Pathophysiology of OCD
2.1. Orbitofrontal Cortex (OFC)
2.1.1. Function: Crucial for reward processing, decision-making, regulating emotions, and social behavior. Helps modify behavior when rewards change, may be especially activated when the differential between the expected and actual reward is signifcant.
2.1.1.1. OCD’s Impact: Abnormalities and increased tracer uptake/hyperactivity. Hypothesized to improperly signal that a task is complete in indivudals with OCD.
2.2. Anterior Cingulate Cortex (ACC)
2.2.1. Function: Involved in decision-making, error detection, emotional regulation, and conflict monitoring. Associated with negative emotional states, such as anxiety.
2.2.1.1. OCD’s Impact: ACC also exhibits hyperactvity in individuals with OCD, particularly in the dorsal section (dACC). Expected to be overactive when the OFC signals that a task is incomplete.
2.2.1.1.1. https://pmc.ncbi.nlm.nih.gov/articles/PMC4476073/#S1
2.3. Basal Ganglia
2.3.1. Function: Responsible for motor control, motor learning, executive functions/behaviors/emotions.
2.3.1.1. OCD’s Impact: Head of the caudate shows increased tracer uptake/hyperactivity in the brain, therefore also contributing to OCD symtoms.
2.4. Thalamus
2.4.1. Function: Relays sensory and motor signals to the cerebral cortex, as well as regulating alertness and sleep.
2.4.1.1. OCD’s Impact: Shows more activation in patients with OCD, provokes compulsive-like behaviors and neurovegetative manifestations which are usually associated with feelings of anxiety in OCD patients.
2.5. Dorsomedial Prefrontal Cortex (dmPFC)
2.5.1. Function: Plays a crucial role in high-level cognitive functioning, particularly in social cognition, self-control, and emotional regulation. (Integrating social information, forming social impressions, understanding others’ perspectives).
2.5.1.1. OCD’s Impact: the dmPFC is a part of the Cortico-Striatal-Thalamic-Cortical Pathway (so is the ACC), and disruptions to this region contribute negatively to the development of OCD symptoms.
3. Current Treatments for OCD``
3.1. Cognitive Behavorial Therapy (CBT)
3.1.1. One of the most common and effective forms of therapy, which helps individuals to identify, challenge, and break negative patterns of thought/cycles and behavior associated with OCD.
3.2. Exposure and Response Prevention Therapy (ERP)
3.2.1. A form of CBT which is primarily used to treat OCD. It involves helping indiciduals gradually confront their fears and obsessions (exposure) and then resisting the urge to perform a compulsion afterward (response prevention).
3.3. Medication
3.3.1. SSRIs
3.3.1.1. Commonly prescribed t patients with OCD to help reduce (the stress of) obsessions and compulsions.
3.3.2. Tricyclic Antidepressants (TCAs)
3.3.2.1. Clomipramine (Anafranil) is a TCA that is specifically approved for OCD treatment. Influences serotonin and norepinephrine reuptake inhibition, reducing the intensity/frequency of obsessions and compulsions.
3.3.2.1.1. https://iocdf.org/about-ocd/treatment/#:~:text=Overview,Learn%20more
3.3.3. Antipsychotics
3.3.3.1. May be used in conjuction with SSRIs of the SSRIs alone are not enough to manage a patient’s OCD symptoms (Augmentation).
4. What is Transcranial Magentic Stimulation (TMS)?
4.1. TMS is a non-invasive brain stimulation technique used to treat various neurological and psychiatric disorders. It involves using magnetic pulses to stimulate specific areas of the brain, altering brain activity and alleviating the patient’s symptoms.
4.2. Current Applications
4.2.1. Major Depressive Disorder (MDD)
4.2.2. Smoking Cessation
4.2.3. Anxiety
5. How could/why should TMS be used to treat OCD?
5.1. TMS can potentially be a great option for people with OCD who have not fully responded to standard first-line treatments like ERP or medication, as it’s non-invasive and uses magnetic fields to target the (hyperactive) areas of the brain which play roles in OCD specifically (e.g. the ACC, dmPFC, OFC, etc.).
5.2. Deep TMS (dTMS)
5.2.1. Uses a specialized coil (H-coil) to target deeper areas of the brain, reaching up to 1.25 inches deep.
5.2.1.1. For dTMS specifically, about 45% of patients experienced reduced OCD symptoms at one month following treatment. Research conducted by BrainsWay, a manufacturer of an FDA-cleared dTMS device for OCD, suggests that this number may actually be over 55%. Some patients may require ‘maintenance’ treatment after a period of time to sustain the results (single sessions every one to two weeks).
5.3. Repetitive TMS (rTMS)
5.3.1. Uses a traditional figure-8 coil to deliver magnetic pulses, only reaching 0.27 inches into the brain.
5.3.1.1. When it comes to rTMS, only areas of the brain closer to the surfave are targeted and have magnetic pulses delivered to them. While a meta-analysis of randomized sham-controlled trials specifically examined rTMS for OCD and found that it exhibited a moderate therapuetic effect, rTMS does not seem to report the same success rates for OCD symtoms as dTMS does. Therefore, it seems dTMS is the better option for OCD patients.
5.4. Side Effects
5.4.1. Headache
5.4.2. Scalp Discomfort
5.4.3. Tingling, spasms, or twitching of facial muscles
5.4.4. Lightheadedness
5.4.5. Seizures (RARE)
5.4.6. Hypomania or mania (RARE, mostly seen in patients who also have Bipolar Disorder)
5.4.7. Note: Some patients may feel mild discomfort during and shortly after treatment. Patients may continue about their daily activites after treatment.
6. Hypothetical TMS Protocol for OCD Treatment
6.1. Device
6.1.1. Deep Transcranial Magnetic Stimulation (dTMS) device, designed to reach deeper into the brain for more effective treatment.
6.2. Target Area(s)
6.2.1. OFC, ACC, Basal Ganglia, Thalamus, dmPFC/CSTC Pathway.
6.3. Stimulation
6.3.1. High frequency stimulation (around 20Hz) should be used, as approved by the FDA.
6.4. Symptom Provocation
6.4.1. Before each dTMS session, the patient will undergo a short, personalized ‘provocation’ to intentionally trigger OCD symptoms. This way, the brain circuit which will be targeted during treatment is active.
6.5. Treatment Schedule
6.5.1. Treatment sessions would be provided in an office setting on an outpatient basis, five days a week over the course of four to six weeks. The actual treatment time, following the ‘provocation’, is 18 minutes.
6.6. Treatment Protocol
6.6.1. During each treatment, the patient will sit in a chair, wear ear plugs, and have the TMS device (sometimes placed within a cushioned helmet) placed against the top of their head. The patient will be awake during treatment and will hear loud clicking sounds, as well as feeling a ‘tapping’ sensation on their scalp.
6.7. Maitenance
6.7.1. After completing the initial course, some patients may require ‘maintenance’ to keep hold of their symptom reduction, which involves returning for sessions every one to two weeks.