EEG Outcomes From Cognitive Behavioural Therapy for Psychosis (EPIC)

July 24, 2025 updated by: Michael Best, University of Toronto
Despite overwhelming evidence for neurocognitive and neurophysiological factors involved in the etiology of psychosis, these factors have never been examined as mechanisms of improvement from CBTp. The first aim in the present study is to examine neurophysiological outcomes from CBTp using electroencephalography (EEG). The second aim is to examine neurocognitive outcomes from CBTp. This is an open-label pilot study. Twenty participants will receive CBTp and will be assessed at baseline and after 4 months.

Study Overview

Status

Completed

Conditions

Intervention / Treatment

Detailed Description

Despite decades of refining traditional treatments for schizophrenia-spectrum disorders, recovery rates remain unchanged at only 13.5%, and there is an urgent need for innovative new interventions. Cognitive behavioural therapy has more recently been applied to treating psychosis and initial evidence has suggested that cognitive behavioural therapy for psychosis (CBTp) is the most effective psychosocial intervention available for psychosis. However, the efficacy of CBTp has been limited to moderate effect sizes. Little is currently understood about the mechanisms of CBTp, and a greater understanding of mechanisms is necessary in order to improve treatment efficacy. Despite overwhelming evidence for neurocognitive and neurophysiological factors involved in the etiology of psychosis, these factors have never been examined as mechanisms of improvement from CBTp. Cognitive behavioural therapy for psychosis (CBTp) has demonstrated efficacy for reducing positive symptoms, negative symptoms, and improving community functioning6 for individuals diagnosed with psychotic disorders. Despite meta-analytic evidence for the efficacy of CBTp, little is known about the neurophysiological processes through which symptomatic and functional change occurs. Electroencephalography (EEG) provides temporally precise measurement of neurophysiological activity. Positive symptoms have been associated with reduced integration of discrepant information as indexed by the N400 event-related potential, reduced resting state power in the EEG alpha frequency band, and reduced cognitive control as indexed by EEG alpha and theta power during cognitive flanker tasks. Additionally, neurocognitive abilities such as attention, memory, and problem solving are the best predictors of community functioning among individuals diagnosed with psychotic disorders. Although CBTp improves community functioning,[6] neurophysiological and neurocognitive outcomes have never been examined as therapeutic mechanisms from CBTp, despite the fact that therapeutic processes would be expected to improve cognitive functions.

Aim 1: Examine neurophysiological outcomes from CBTp using EEG.

Aim 2: Examine neurocognitive outcomes from CBTp

Hypothesis 1: After CBTp it is expected that participants will have a) increased N400 amplitude; b) increased resting state EEG alpha power; and c) reduced alpha and increased theta power during a flanker task

Hypothesis 2: After CBTp participants will have increased global neurocognitive abilities as indexed by a neurocognitive composite score.

Although CBTp has demonstrated efficacy to improve symptoms for individuals experiencing psychosis, little is known about the neurophysiological process through which this improvement occurs, and neither EEG nor neurocognitive outcomes from CBTp have ever been examined. The current results will provide preliminary evidence for neurophysiological mechanisms of change from CBTp that will increase understanding of the disorder and provide critical insights for refining psychotherapeutic interventions. Additionally, psychotherapy trials typically only examine psychological outcomes, however, if CBTp is effective it would be expected that this could be detected at both the neurophysiological level and neurocognitive level as well. My incorporation of multiple levels of assessment in clinical trials was recently praised as a goldstandard approach to trial methodology. This line of research is critical to improving the efficacy of CBTp.

Study Type

Interventional

Enrollment (Actual)

20

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • Canada
    • Ontario
      • Scarborough, Ontario, Canada, M1C 1A4
        • University of Toronto Scarborough

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

18 years to 65 years (Adult, Older Adult)

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • The inclusion criteria is anyone who meets the criteria of schizophrenia, schizoaffective disorder or any other psychotic disorder, are also 18-65 years of age, are not abusing drugs or alcohol and can read and speak English. Participants must be experiencing active symptoms of psychosis as indicated on the PANSS.

Exclusion Criteria:

  • Exclusion criteria include anyone with a neurological disease or neurological damage, medical illnesses that can change neurocognitive function, a medical history of head injury with loss of consciousness and those with physical handicaps that would prevent them from engaging in assessment procedures

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: N/A
  • Interventional Model: Single Group Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Cognitive Behavioural Therapy for psychosis
CBTp will be delivered according to an established manual that the PI has previously used successfully for in-person treatment. Treatment will consist of individual sessions with a psychologist employed by the University of Toronto for 1-hour per week for 6-months, or by one of the listed clinical graduate students under his supervision. All treatment will be delivered in-person. This treatment will be delivered in addition to usual care and no changes to usual care will be required.
Behavioral: Cognitive Behavioural Therapy for Psychosis
CBT will be delivered according to an established manual that the PI has previously used successfully for in-person treatment. Treatment will consist of individual sessions with a psychologist employed by the University of Toronto for 1-hour per week for 6-months, or by one of the listed clinical graduate students under his supervision. All treatment will be delivered in-person. This treatment will be delivered in addition to usual care and no changes to usual care will be required.
Other Names:
  • CBT
  • CBTp

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Positive and Negative Syndrome Scale (PANSS) Total Score
Time Frame: Change from Baseline to Follow-up (6 months post treatment)
The PANSS is a 30-item semi-structured interview assessing positive, negative symptoms and general psychopathology. Each item is scored on a 7-point scale (1 = absent, 2 = minimal, 3 = mild, 4 = moderate, 5 = moderate severe, 6 = severe, 7 = extreme). The lowest score would be a 30 and the highest score would be 210. A higher score would indicate increased symptomology.
Change from Baseline to Follow-up (6 months post treatment)

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Personal and Social Performance Scale (PSP)
Time Frame: Change from Baseline to Follow-up (6 months post treatment)
The PSP assesses community functioning through a brief interview with the participant about their daily activities. It contains 4 areas: (1) socially useful activities; including work and study; (2) personal and social relationships; (3) self-care; (4) disturbing and aggressive behaviors. The total score ranges from 1 to 100 and is interpreted on a 10-point intervals. Lower scores indicates more severe functional impairment while higher scores indicate better functioning.
Change from Baseline to Follow-up (6 months post treatment)
The Psychotic Symptom Rating Scales (PSYRATS)
Time Frame: Change from Baseline to Follow-up (6 months post treatment)
The PSYRATS assesses frequency and distress associated with the experiences of auditory hallucinations and delusions based on the PANSS interview. Each of the 17 items is scored on a 5-point scale, where a score of 0 indicates no presence, and 4 indicates the highest severity. The lowest score would be a 0 and the highest score would be 68. A higher score would indicate increased symptomology.
Change from Baseline to Follow-up (6 months post treatment)
Calgary Depression Scale for Schizophrenia (CDSS)
Time Frame: Change from Baseline to Follow-up (6 months post treatment)
The CDSS is a 9-item interview-based measure of depression symptoms specifically designed for use with people experiencing schizophrenia. Each item is scored on a 4-point scale (0 = absent, 1 = mild, 2 = moderate, 4 = severe). The lowest score would be a 0 and the highest score would be 36. A higher score would indicate increased severity of depressive symptoms.
Change from Baseline to Follow-up (6 months post treatment)
The Questionnaire About the Process of Recovery (QPR)
Time Frame: Change from Baseline to Follow-up (6 months post treatment)
QPR is a self-report measure assessing recovery with people experiencing psychosis. This version contains 22 items while the response to each statement is scored on a 5-point Likert scale ranging from "0 = strongly disagree" to "4 = strongly agree". The lowest possible score is 0 and the highest score could be 88. Higher scores would indicate better recovery.
Change from Baseline to Follow-up (6 months post treatment)
Beliefs About Paranoia Scale (BAPS)
Time Frame: Change from Baseline to Follow-up (6 months post treatment)
The BAPS is a 31-item self-report measure assessing metacognitive beliefs about paranoia. The degree of agreement to each statement is scored on a 4-point scale (1 = not at all, 2 = somewhat, 3 = moderately so, 4 = very much). Scales include positive, negative and normalizing beliefs about paranoia, and paranoia as a survival strategy. The lowest score would be 31 and the highest score would be 124. Higher scores are indicative of more beliefs and are shown to be related to paranoid ideation.
Change from Baseline to Follow-up (6 months post treatment)
Beliefs About Voices Questionnaire (BAVQ)
Time Frame: Change from Baseline to Follow-up (6 months post treatment)
BAVQ-R is a 35-item self-report measure assessing metacognitive perception, feelings about and reaction to auditory hallucinations. The degree of agreement to each statement is scored on a 4-point scale, ranging from disagree to strongly agree. Five subscales (malevolence, benevolence, omnipotence, resistance, engagement) are included. The lowest possible score is 0 and the highest score would be 105. Higher scores would indicate a tighter relationship with voices.
Change from Baseline to Follow-up (6 months post treatment)
Experiences Questionnaire (EQ)
Time Frame: Change from Baseline to Follow-up (6 months post treatment)
The EQ is a 11-item self-report measure assessing observations of thoughts and self. Frequency of experiences is scored on a 5-point scale, ranging from "1 = never" to "5 = all the time". The lowest possible score is 11 while the highest score would be 55. Higher scores would indicate increased levels of self-acceptance and mindfulness.
Change from Baseline to Follow-up (6 months post treatment)
Brief Core Schema Scale (BCSS)
Time Frame: Change from Baseline to Follow-up (6 months post treatment)
The BCSS is a 24-item self-report measure assessing positive and negative judgments individuals hold about themselves and others. Responses are first given dichotomously as "no" or "yes". "No" is scored as 0 and if the answers are "yes", the intensity of beliefs are then rated on a 4-point scale (1 = believe it slightly, 2 = believe it moderately, 3 = believe it very much, 4 = believe it totally). The lowest score would be a 0 and the highest score would be a 96. Higher scores in the positive-self subscale indicate more positive beliefs about selves, while higher scores in the negative-self subscale indicate more negative beliefs about selves. Higher scores in the positive-others subscale indicate more positive beliefs about others, while higher scores in the negative-others subscale indicate more negative beliefs about others.
Change from Baseline to Follow-up (6 months post treatment)
Dysfunctional Attitude Scale (DAS)
Time Frame: Change from Baseline to Follow-up (6 months post treatment)
DAS is a 40-item self-report measure assessing dysfunctional beliefs. The degree of agreement to each statement is scored on a 7-point Likert scale (1 = agree totally, 2 = agree very much, 3 = agree slightly, 4 = neutral, 5 = disagree slightly, 6 = disagree very much, 7 = disagree totally). The lowest possible scale is 40 while the highest possible scale is 280. Higher scores would indicate more negative beliefs.
Change from Baseline to Follow-up (6 months post treatment)
Davos Assessment of Cognitive Biases Scale (DACOBS)
Time Frame: Change from Baseline to Follow-up (6 months post treatment)
DACOBS is a 42-item self-report inventory assessing cognitive processing biases associated with psychosis. The degree of agreement to each statement is scored on a 7-point Likert scale, ranging from "1 = strongly disagree" to "7 = strongly agree". The lowest score would be a 42 and the highest score would be a 294. Higher scores would indicate more cognitive biases.
Change from Baseline to Follow-up (6 months post treatment)
Childhood Trauma Questionnaire (CTQ)
Time Frame: Change from Baseline to Follow-up (6 months post treatment)
The CTQ is a 28-item self-report measure assessing experiences of trauma during childhood. Frequency of experiences is reported on a 5-point scale, ranging from "never true" to "very often true". Reverse-coded items are included. The lowest score would be a 28 and the highest score would be a 140. Higher scores would indicate more trauma exposure.
Change from Baseline to Follow-up (6 months post treatment)
Working Alliance Inventory (WAI)
Time Frame: Change from Baseline to Follow-up (6 months post treatment)
The WAI assesses the quality of the therapeutic relationship. 36 items are to be completed both by the therapist and the client. Frequency of experiences are rated on a 7-point Likert scale (1 = never, 2 = rarely, 3 = occasionally, 4 = sometimes, 5 = often, 6 = very often, 7 = always). Reverse-coded items are included. The lowest score would be a 36 and the highest score would be a 252. Highest scores would indicate more therapeutic alliance.
Change from Baseline to Follow-up (6 months post treatment)
Psychological Distance Scaling Task (PDST)
Time Frame: Change from Baseline to Follow-up (6 months post treatment)
The PDST is an experimental task associated with cognitive processing biases in psychosis. It gives measure of both how positive and negative a person views themselves, and how tightly held these beliefs are based on the clustering of the ratings. Participants would place adjectives on the grid based on self-descriptiveness and valence, while responses ranging from "not at all like me" to "very much like me" and "very negative" to "very positive". Smaller interstimulus distances among negative self-relevant adjectives and greater interstimulus distances among positive self-relevant adjectives would indicate more negative biases about selves.
Change from Baseline to Follow-up (6 months post treatment)

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

University of Toronto

Collaborators

Ontario Shores Centre for Mental Health Sciences

Investigators

  • Principal Investigator: Michael W Best, Ph.D., University of Toronto

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

February 1, 2023

Primary Completion (Actual)

November 13, 2024

Study Completion (Actual)

November 13, 2024

Study Registration Dates

First Submitted

January 19, 2023

First Submitted That Met QC Criteria

January 19, 2023

First Posted (Actual)

January 30, 2023

Study Record Updates

Last Update Posted (Actual)

July 29, 2025

Last Update Submitted That Met QC Criteria

July 24, 2025

Last Verified

July 1, 2024

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • 38831 (Organon)

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

product manufactured in and exported from the U.S.

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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