An interventional study of Low-intensity focused ultrasound (Active) and Low-intensity focused ultrasound (Sham) in Obsessive Compulsive Disorder (OCD), sponsored by University of Calgary. Not yet recruiting at 1 site in Canada. Open to participants aged 18 Years to 70 Years. Per ClinicalTrials.gov, last updated 2026-10-14.
Sponsored by University of Calgary · Not applicable, Interventional, and Treatment
The goal of this clinical trial is to learn whether low-intensity focused ultrasound (LIFU), a non-invasive form of brain stimulation, can change brain activity and improve thinking and decision-making in adults with obsessive-compulsive disorder (OCD). The main questions it aims to answer are:
Can active LIFU change activity in brain pathways involved in OCD? Can active LIFU improve the ability to control thoughts and actions?
Researchers will compare active LIFU with sham LIFU to see whether active LIFU causes changes in brain activity and performance on behavioral tasks.
Participants will:
Complete questionnaires and behavioral tasks. Have magnetic resonance imaging (MRI) scans to measure brain activity and identify the area to receive LIFU.
Receive both active and sham LIFU on separate visits. Have MRI scans and complete behavioral tasks after each LIFU session. Complete assessments of OCD symptoms, safety, and possible side effects.
Obsessive-compulsive disorder (OCD) is a mental health condition characterized by unwanted and difficult-to-control thoughts, images, or urges, often accompanied by repeated behaviors or mental acts. OCD can cause substantial problems in daily life and reduce quality of life. Current treatments include medication and cognitive behavioral therapy, but many people with OCD do not achieve remission. Therefore, there is a need to develop new treatment approaches.
Research using brain imaging suggests that OCD is associated with abnormal activity in a network of connected brain regions called the cortico-striato-thalamo-cortical (CSTC) circuit. The anterior limb of the internal capsule (ALIC) is an important pathway within this circuit and connects several brain regions involved in OCD. The ALIC has therefore been used as a target for treatments that directly change brain activity in people with severe OCD.
Low-intensity focused ultrasound (LIFU) is a non-invasive brain stimulation method that uses focused ultrasound waves to change brain activity. Unlike some other non-invasive brain stimulation methods, LIFU can reach areas deep in the brain with a high degree of precision. This study will investigate whether LIFU targeting the ALIC can change brain activity and cognitive function in people with OCD.
This is a pilot exploratory clinical trial using a randomized crossover design. Each participant will receive both active and sham LIFU on separate study visits, with the order determined randomly. This design allows the effects of active LIFU to be compared with sham LIFU within the same participant.
Before LIFU, participants will undergo magnetic resonance imaging (MRI). Diffusion MRI will be used to examine brain connections and identify an individualized target within the ALIC for each participant. Computer simulation will also be used to plan how the ultrasound will reach the selected target.
Brain imaging will be performed before and after LIFU to examine changes in communication between brain regions. Participants will also complete behavioral tasks that measure cognitive control and impulsivity. Clinical symptoms and possible side effects will be assessed during the study.
The main purpose of this study is to determine whether active LIFU can change brain connectivity related to OCD and improve cognitive control compared with sham LIFU. The study will also collect preliminary information about changes in OCD symptoms and the safety and tolerability of LIFU. The findings may help determine whether this approach should be investigated further as a possible non-invasive treatment for OCD.
626 studies on the registry are indexed under Obsessive-Compulsive Disorder; 162 are open to participants now.
This study's planned enrollment of 20 is below the median of 45 across 510 interventional studies indexed under Obsessive-Compulsive Disorder.
Browse Obsessive-Compulsive Disorder studies →University of Calgary is the lead sponsor of 699 studies on the registry; 192 are open to participants now.
Of its 10 completed or terminated interventional studies of FDA-regulated products, 2 (20%) have results posted.
Counted across the registry records on this site, refreshed daily.
Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Exclusion Criteria:
Participants will receive active LIFU during the first stimulation visit, followed by sham LIFU during the second stimulation visit one week later.
Device: Low-intensity focused ultrasound (Active) · Device: Low-intensity focused ultrasound (Sham)
Participants will receive sham LIFU during the first stimulation visit, followed by active LIFU during the second stimulation visit one week later.
Device: Low-intensity focused ultrasound (Active) · Device: Low-intensity focused ultrasound (Sham)
Low-intensity focused ultrasound (LIFU) will be delivered using an in-house system with a 128-element focused-ultrasound array operating at 500 kHz. The stimulation parameters are a pulse repetition frequency of 100 Hz, pulse duration of 1 ms, duty cycle of 10%, and pulse train duration of 90 seconds. LIFU will be delivered to an individualized target within the anterior limb of the internal capsule (ALIC) that has the strongest connection to the prefrontal cortex, identified using diffusion MRI and probabilistic tractography. Sham LIFU will be delivered during the sham condition.
Sham LIFU will be delivered to the third ventricle using the same LIFU system.
Changes in functional connectivity between the ALIC and prefrontal cortex
Resting-state functional MRI will be used to measure functional connectivity between the anterior limb of the internal capsule (ALIC) and the prefrontal cortex. Functional connectivity will be quantified as a standardized coefficient between the ALIC and the prefrontal cortex. The outcome will be the change in functional connectivity from baseline to immediately after LIFU. Changes following active and sham LIFU will be compared.
Time frame: Baseline and immediately after each LIFU session (sessions approximately 1 week apart).
Change in reaction time on the Multi-Source Interference Task (MSIT)
Reaction time (milliseconds) will be measured during the MSIT to assess cognitive control. The outcome will be the change in reaction time from baseline to immediately after LIFU. Changes following active LIFU will be compared with changes following sham LIFU.
Time frame: Baseline and immediately after each LIFU session (sessions approximately 1 week apart).
Change in accuracy on the Multi-Source Interference Task (MSIT)
Accuracy (percentage) will be measured during the MSIT to assess cognitive control. The outcome will be the change in accuracy from baseline to immediately after LIFU. Changes following active LIFU will be compared with changes following sham LIFU.
Time frame: Baseline and immediately after each LIFU session (sessions approximately 1 week apart).
Change in BOLD activation in the prefrontal cortex during the Multi-Source Interference Task (MSIT)
Task-based functional MRI will be used to measure blood oxygen level-dependent (BOLD) activation within the prefrontal cortex during the MSIT. BOLD activation will be quantified using a standardized measure. The outcome will be the change in BOLD activation from baseline to immediately after LIFU. Changes following active and sham LIFU will be compared.
Time frame: Baseline and immediately after each LIFU session (sessions approximately 1 week apart).
Changes in probability of correct choice on the Information Sampling Task (IST)
The probability of making a correct choice will be measured during the IST to assess decision-making and impulsivity. The outcome will be the change in the probability of making a correct choice from baseline to immediately after LIFU. Changes following active LIFU will be compared with changes following sham LIFU.
Time frame: Baseline and immediately after each LIFU session (sessions approximately 1 week apart).
Changes in Yale-Brown Obsessive-Compulsive Scale (Y-BOCS) score
OCD symptom severity will be assessed using Yale-Brown Obsessive-Compulsive Scale (Y-BOCS). Changes in Y-BOCS scores will be compared between active and sham LIFU conditions.
Time frame: Baseline and 1 week after each LIFU session.
Changes in Overall Anxiety Severity and Impairment Scale (OASIS) score
Anxiety severity will be assessed using the Overall Anxiety Severity and Impairment Scale (OASIS). Changes in OASIS scores will be compared between active and sham LIFU conditions.
Time frame: Baseline and 1 week after each LIFU session.
Changes in Patient Health Questionnaire-9 (PHQ-9) score
Depression severity will be assessed using Patient Health Questionnaire-9 (PHQ-9). Changes in PHQ-9 scores will be compared between active and sham LIFU conditions.
Time frame: Baseline and 1 week after each LIFU session.
Changes in Ruminative Responses Scale (RRS) score
Rumination severity will be assessed using Ruminative Responses Scale (RRS). Changes in RRS scores will be compared between active and sham LIFU conditions.
Time frame: Baseline and 1 week after each LIFU session.
Incidence of adverse events
Adverse events and side effects will be assessed throughout the study, from the first LIFU session to 1 week after the final LIFU session. The proportion of participants experiencing adverse events (percentage) will be recorded and compared between active and sham LIFU conditions. Adverse events will be categorized according to severity and relationship to the procedure and device.
Time frame: From the first LIFU session to 1 week after the final LIFU session.
Plan to share: Undecided — There are currently no plans to use the data for future research beyond the purposes of this study.This study will not create a research database or registry for future research use. De-identified studydata will be retained indefinitely in accordance with the study protocol.
No publications or documents are linked to this record.
From the registry record's own update history. This site started tracking changes on Sep 25, 2026; for anything earlier, see the record history on ClinicalTrials.gov ↗
This study is not yet recruiting, as verified in Aug 2026. You cannot join it, but the record below documents what was studied.
Get an email when the registry record changes — status, dates, results — or when someone posts here.
Sign in to followQuestions and observations about this study, from anyone following it. Not medical advice, and not a channel to the study team — their contact details are on the registry record.
Sign in to join the discussion. Reading takes no account; posting does. You choose a display name, and a pseudonym is the default.
Nothing here yet. If you are running this trial, taking part in it, or weighing whether to, this is the place to say so.
Obsessive-Compulsive Disorder →