The present study aims to investigate whether transcranial direct current stimulation (tDCS) reduces auditory hallucinations in patients with psychosis. In addition, the neuronal changes of tDCS will be examined.
The majority of patients with psychosis experience hallucinations, particularly auditory hallucinations are frequent. The hallucinations often leads to massive distress and impairments in social functioning and sometimes even order patients to commit acts of violence against themselves or others. The standard treatment for auditory hallucinations is antipsychotic medication. However, side-effects can be severe and about 25-30% of the patients do not respond to the medication. Transcranial direct current stimulation is a non-invasive brain stimulation technique, which modulates cortical excitability in a pain-free free with mild transient adverse effects, if any. Typically, cortical excitability underneath the anode is boosted while cathodal stimulation has inhibitory effects. Previous studies found that 2 daily sessions of 20 min tDCS for five subsequent days may reduce auditory hallucinations. Investigators want to further assess the efficacy of tDCS in sample that is large enough to detect medium to large effects. In addition, investigators want to investigate the neural mechanisms that underlie the tDCS treatment by examining various neuroimaging parameters before, immediately after treatment, and 3 months after treatment.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
TRIPLE
Enrollment
24
University of Bergen
Bergen, Hordaland, Norway
Auditory Hallucination Rating Scale (AHRS)
Measure for severity of hallucinations
Time frame: Change from Baseline to immediately after treatment and 3 months after treatment
Questionnaire for Psychotic Experiences (QPE)
Measure for severity of hallucinations
Time frame: Change from Baseline to immediately after treatment and 3 months after treatment
Positive and Negative Syndrome Scale (PANSS)
Measure for positive and negative symptoms in psychotic disorders
Time frame: Change from Baseline to immediately after treatment and 3 months after treatment
Hallucinations App
iPhone/iPod application for self-ratings of auditory hallucinations
Time frame: Continuously between baseline and 3 months after treatment
Hallucination Change Scale (HCS)
Measure for changes in severity of auditory hallucinations
Time frame: Change from Baseline to immediately after treatment and 3 months after treatment
Stroop task
Measure of executive functioning
Time frame: Change from Baseline to immediately after treatment and 3 months after treatment
Trailmaking test A and B
Measure of visuomotor speed
Time frame: Change from Baseline to immediately after treatment and 3 months after treatment
Expectations Questionnaire
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prior expectations participants have regarding the outcome of the treatment on a scale from 0 ("The treatment will have no effect") to 10 ("The treatment will make the voices go away entirely.")
Time frame: Change from Baseline to immediately after treatment and 3 months after treatment
Adverse Effects Questionnaire
The presence and severity of side-effects will be monitored using the tDCS adverse effects questionnaire
Time frame: The questionnaire is completed after each tDCS session. That is, twice on each day of the five day treatment program
The Clinical Global Impressions Scale - Severity
Measure of global functioning
Time frame: Change from Baseline to immediately after treatment and 3 months after treatment
Global Assessment of Functioning
Measure of global functioning
Time frame: Change from Baseline to immediately after treatment and 3 months after treatment
Shape, size, and integrity of gray and white matter structures in the brain
Structural Magnetic Resonance Imaging (MRI)
Time frame: Change from Baseline to immediately after treatment and 3 months after treatment
GABA and glutamate levels in the dorsolateral prefrontal cortex and peri-Sylvian regions
MR spectroscopy
Time frame: Change from Baseline to immediately after treatment and 3 months after treatment
BOLD (Blood Oxygenation Level Dependent signal) response during resting state
Resting state functional MRI
Time frame: Change from Baseline to immediately after treatment and 3 months after treatment
Dichotic listening paradigm
Measure of executive functioning
Time frame: Change from Baseline to immediately after treatment and 3 months after treatment
Dichotic listening paradigm
Measure of language lateralization
Time frame: Change from Baseline to immediately after treatment and 3 months after treatment
BOLD response during dichotic listening paradigm
Changes in brain activity in the left dorsolateral prefrontal cortex and the peri-Sylvian language regions
Time frame: Change from Baseline to immediately after treatment and 3 months after treatment
White matter structure and connectivity
MR Diffusion Tensor Imaging
Time frame: Change from Baseline to immediately after treatment and 3 months after treatment