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

What this study is about

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).

Who can join (things the study team will check)

✅ You may be able to join if…

• Male or female participants of any race or ethnicity
• Inpatients or outpatients ≥18 years of age
• DSM-V diagnosis of schizophrenia or schizoaffective disorder
• Capable of consenting to participate in the research study
• 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.

🚫 You may not be able to join if…

• Unwilling or incapable to consent to the study based on the MacArthur Test of Competence
• Unstable medical or any concomitant major medical or neurological illness, including a history of seizures
• Acute suicidal or homicidal ideation
• Formal thought disorder rating ≥3 on the Positive and Negative Syndrome Scale (PANSS) P2 conceptual disorganization item
• DSM-V substance dependence (except caffeine, nicotine, and cannabis/marijuana) within 1 month of entering the study
• Positive urine drug screen except for cannabis/marijuana at the screening visit
• Metal implants or pacemaker precluding an MRI scan or other contraindications to MRI (e.g., claustrophobia)
• Pregnancy
• Score <32 on the Wide Range Achievement Test-III Additional exclusion criteria for this companion study are:
• Unwilling or incapable to consent to the study based on the MacArthur Test of Competence
• Exposure to long-acting injectable antipsychotics in the last 6 months
• Exceeding allowed annual radiation exposure levels (20 mSv), as outlined by our PET Centre guidelines
• Receiving treatment with medications such as levetiracetam that blocks SV2a binding
• Disorders of coagulation or taking anticoagulant medication
• Having completed multiple PET scans in the past, such that participation in this study would cause participant to exceed lifetime limit (8 PET scans)

Where this trial is running

• Centre for Addiction and Mental Health, Toronto, Ontario, Canada

Who to contact

Philip Gerretsen, MD, PhD · 416-535-8501 · philip.gerretsen@camh.ca

It's completely normal to call and ask questions before deciding anything. Mention the study ID: NCT05435300.