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.

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.

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)