The Effects of tDCS on Illness Awareness in Schizophrenia

The Clinical and Functional Imaging Effects of Transcranial Direct Current Stimulation (tDCS) on Illness Awareness in Schizophrenia

This is a novel study that seeks to explore the clinical and functional imaging effects of transcranial direct current stimulation (tDCS) on illness awareness or anosognosia in schizophrenia, arguably the most treatment-resistant manifestation of the disorder.

Study Overview

• Status: Completed
• Conditions: Schizophrenia
• Intervention / Treatment: Other: Active TDCS; Other: Sham TDCS

Detailed Description

Transcranial DCS is a novel, non-invasive and non-convulsive technique for altering brain function. To our knowledge, no research has investigated the functional and behavioural effects of tDCS on anosognosia in schizophrenia. As such, we aim to improve impaired illness awareness in schizophrenia with tDCS by inhibiting left hemisphere regions (i.e. temporoparietooccipital cortex) shown by our group to be activated during illness denial.

Positive results will demonstrate that impaired illness awareness in schizophrenia involves a similar brain network to impaired illness awareness in patients with brain lesions and can be similarly modulated with non-invasive techniques, such as tDCS. If proven effective, this easy to administer, safe, non-invasive intervention would have the potential to alter individuals' attitude towards their illness and medication, leading ultimately to an improvement in individuals' capacity for illness recognition and treatment engagement, which would undoubtedly have a significant impact on the management of this devastating mental disorder.

• Study Type: Interventional
• Enrollment (Actual): 32
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Canada
  • Ontario
    • Toronto, Ontario, Canada, M5S 2S1
      • Centre for Addiction and Mental Health

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 14 years and older (Adult, Older Adult)
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

1. Male or female inpatients or outpatients ≥ 18 years of age
2. Having a DSM-IV diagnosis of schizophrenia or schizoaffective disorder
3. Voluntary and capable of consenting to participation in the research study
4. Fluent in English
5. Moderate-to-severe lack of illness awareness (≥3 on PANSS G12 Insight and Judgment item)
6. On a stable dose of antipsychotic and other concomitant medications, and unlikely to undergo changes in dose during the study

Exclusion Criteria:

1. Serious unstable medical illness or any concomitant major medical or neurological illness, including a history of seizures or a first degree relative with a history of a seizure disorder
2. Acute suicidal and/or homicidal ideation
3. Formal thought disorder rating of over 2 on the (Scale for Assessment of Positive Symptoms) SAPS.
4. DSM-IV substance dependence (except caffeine and nicotine) within one month prior to entering the study
5. Pregnant women
6. Mild lack of insight to good illness awareness (<3 on PANSS G12 Insight and Judgment item).
7. Positive urine drug screen for drugs of abuse
8. Currently taking antiepileptics
9. Any contraindications to MRI (eg., metal implants that would preclude an MRI, claustrophobia)
10. Score < 32 on the Wide Range Achievement Test-III (WRAT III)

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Basic Science
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Double

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Active TDCS; Participants who are randomly assigned to this arm will receive dual hemisphere parietal (P3 cathodal, P4 anodal) stimulation daily for 10 days. Each participant will have two MRI scans and their degree of illness awareness assessed at baseline and after 10 days of tDCS. Illness awareness will be assessed weekly thereafter for 4 weeks.	Other: Active TDCS; Participants will receive active tDCS stimulation.
Experimental: Sham TDCS; Participants who are randomly assigned to this arm will receive dual hemisphere sham stimulation with electrodes placed on the parietal lobes (P3 and P4) daily for 10 days. Each participant will have two MRI scans and their degree of illness awareness assessed at baseline and after 10 days of tDCS. Illness awareness will be assessed weekly thereafter for 4 weeks.	Other: Sham TDCS; Participants will receive sham tDCS stimulation

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Illness awareness	The primary aim of this study is to determine if dual hemisphere tDCS daily for 10 days will lead to an improvement in illness awareness versus a control condition (sham tDCS), as measured by changes in illness awareness scores post intervention (10 days post tDCS and weekly x 4 weeks post tDCS) in participants with schizophrenia.	At baseline and weekly for 4 weeks after tDCS

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Neural activity	A secondary aim of this study is to assess changes in brain network activity (blood oxygen level dependent-BOLD) before and after tDCS while performing an illness awareness task during functional MRI.	At baseline and post TDCS

Collaborators and Investigators

• Sponsor: Centre for Addiction and Mental Health
• Investigators: Principal Investigator: Philip Gerretsen, MD, PhD, Centre for Addiction and Mental Health

Publications and helpful links

Helpful Links

• Description: 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.

Study record dates

Study Major Dates

• Study Start (Actual): August 1, 2016
• Primary Completion (Actual): May 13, 2025
• Study Completion (Actual): May 13, 2025

Study Registration Dates

• First Submitted: July 15, 2016
• First Submitted That Met QC Criteria: July 26, 2016
• First Posted (Estimated): July 29, 2016

Study Record Updates

• Last Update Posted (Actual): June 6, 2025
• Last Update Submitted That Met QC Criteria: June 5, 2025
• Last Verified: June 1, 2025

More Information

Terms related to this study

• Keywords: Magnetic resonance imaging; Anosognosia; Electrical stimulation of the brain
• Additional Relevant MeSH Terms: Schizophrenia Spectrum and Other Psychotic Disorders; Mental Disorders; Schizophrenia
• Other Study ID Numbers: 043-2016

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO