Does tDCS Change Synaptic Density in the Brains of Patients With Schizophrenia

NCT ID: NCT05435300

Last Updated: 2025-09-23

Study Results

Results pending

The study team has not published outcome measurements, participant flow, or safety data for this trial yet. Check back later for updates.

Basic Information

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Recruitment Status

RECRUITING

Total Enrollment

20 participants

Study Classification

OBSERVATIONAL

Study Start Date

2021-09-17

Study Completion Date

2026-03-31

Brief Summary

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This study will examine changes in synaptic density with transcranial direct current stimulation (tDCS) in the brains of patients with schizophrenia. Synaptic density levels will be measured using a novel positron emission tomography (PET) radiotracer \[18F\]SDM-8, which is currently the best-in-class method to quantify synaptic density in humans. This will be a companion study to a parent study by our group examining the effects of tDCS on treatment adherence in schizophrenia (REB #103-2018).

Detailed Description

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The aim of our study is to examine if tDCS induces synaptic density changes in patients with schizophrenia using \[18F\]SDM-8. Our study will help elucidate the mechanism through which tDCS affects the brain.

PET scans will be offered to participants that meet the inclusion and exclusion criteria at the initial screening visit. Participants will be scanned with the novel PET tracer \[18F\]SDM-8 to quantify synaptic density levels. PET scans will be timed to coincide to the two time-points, before and after 2-weeks of tDCS treatment that is completed under the parent study protocol (REB #103-2018). Clinical assessments will be done at the same time.

Conditions

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Schizophrenia Schizoaffective

Study Design

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Observational Model Type

CASE_ONLY

Study Time Perspective

PROSPECTIVE

Study Groups

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Schizophrenia/Schizoaffective Disorder

Participants with Schizophrenia/Schizoaffective Disorder and currently enrolled in the tDCS-adherence parent study (REB# 103-2018).

PET Scan

Intervention Type OTHER

Participants will undergo two PET scans throughout the study.

Interventions

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PET Scan

Participants will undergo two PET scans throughout the study.

Intervention Type OTHER

Eligibility Criteria

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Inclusion Criteria

1. Male or female participants of any race or ethnicity
2. Inpatients or outpatients ≥18 years of age
3. DSM-V diagnosis of schizophrenia or schizoaffective disorder
4. Capable of consenting to participate in the research study
5. On a stable dose of oral antipsychotic drug and other concomitant medications for at least 2 months, and unlikely to undergo changes in dose during the study.

Exclusion Criteria

1. Unwilling or incapable to consent to the study based on the MacArthur Test of Competence
2. Unstable medical or any concomitant major medical or neurological illness, including a history of seizures
3. Acute suicidal or homicidal ideation
4. Formal thought disorder rating ≥3 on the Positive and Negative Syndrome Scale (PANSS) P2 conceptual disorganization item
5. DSM-V substance dependence (except caffeine, nicotine, and cannabis/marijuana) within 1 month of entering the study
6. Positive urine drug screen except for cannabis/marijuana at the screening visit
7. Metal implants or pacemaker precluding an MRI scan or other contraindications to MRI (e.g., claustrophobia)
8. Pregnancy
9. Score \<32 on the Wide Range Achievement Test-III


1. Unwilling or incapable to consent to the study based on the MacArthur Test of Competence
2. Exposure to long-acting injectable antipsychotics in the last 6 months
3. Exceeding allowed annual radiation exposure levels (20 mSv), as outlined by our PET Centre guidelines
4. Receiving treatment with medications such as levetiracetam that blocks SV2a binding
5. Disorders of coagulation or taking anticoagulant medication
6. Having completed multiple PET scans in the past, such that participation in this study would cause participant to exceed lifetime limit (8 PET scans)
Minimum Eligible Age

18 Years

Eligible Sex

ALL

Accepts Healthy Volunteers

No

Sponsors

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Centre for Addiction and Mental Health

OTHER

Sponsor Role lead

Responsible Party

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Responsibility Role SPONSOR

Principal Investigators

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Philip Gerretsen, MD, PhD

Role: PRINCIPAL_INVESTIGATOR

Centre for Addiction and Mental Health

Locations

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Centre for Addiction and Mental Health

Toronto, Ontario, Canada

Site Status RECRUITING

Countries

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Canada

Central Contacts

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Philip Gerretsen, MD, PhD

Role: CONTACT

416-535-8501 ext. 39426

Ariel Graff, MD, PhD

Role: CONTACT

416-535-8501 ext. 34834

Facility Contacts

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Philip Gerretsen, MD, PhD

Role: primary

416-535-8501 ext. 39426

Ariel Graff, MD, PhD

Role: backup

416-535-8501 ext. 34834

Related Links

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https://www.camh.ca/en/science-and-research

The Centre for Addiction and Mental Health (CAMH) is the leading mental health and addictions research facility in Canada, and one of the largest in the world.

Other Identifiers

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118/2020

Identifier Type: -

Identifier Source: org_study_id

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