An interventional study of Cognitive Behavioural Therapy for Psychosis in Psychotic Disorders and Schizophrenia and Related Disorders, sponsored by University of Toronto. Completed at 1 site in Canada. Open to participants aged 18 Years to 65 Years. Per ClinicalTrials.gov, last updated 2025-07-29.
Sponsored by University of Toronto · Not applicable, Interventional, and Treatment
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.
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.
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Exclusion Criteria:
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.
Also known as: CBT, CBTp
Positive and Negative Syndrome Scale (PANSS) Total Score
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.
Time frame: Change from Baseline to Follow-up (6 months post treatment)
Personal and Social Performance Scale (PSP)
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.
Time frame: Change from Baseline to Follow-up (6 months post treatment)
The Psychotic Symptom Rating Scales (PSYRATS)
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.
Time frame: Change from Baseline to Follow-up (6 months post treatment)
Calgary Depression Scale for Schizophrenia (CDSS)
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.
Time frame: Change from Baseline to Follow-up (6 months post treatment)
The Questionnaire About the Process of Recovery (QPR)
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.
Time frame: Change from Baseline to Follow-up (6 months post treatment)
Beliefs About Paranoia Scale (BAPS)
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.
Time frame: Change from Baseline to Follow-up (6 months post treatment)
Beliefs About Voices Questionnaire (BAVQ)
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.
Time frame: Change from Baseline to Follow-up (6 months post treatment)
Experiences Questionnaire (EQ)
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.
Time frame: Change from Baseline to Follow-up (6 months post treatment)
Brief Core Schema Scale (BCSS)
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.
Time frame: Change from Baseline to Follow-up (6 months post treatment)
Dysfunctional Attitude Scale (DAS)
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.
Time frame: Change from Baseline to Follow-up (6 months post treatment)
Davos Assessment of Cognitive Biases Scale (DACOBS)
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.
Time frame: Change from Baseline to Follow-up (6 months post treatment)
Childhood Trauma Questionnaire (CTQ)
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.
Time frame: Change from Baseline to Follow-up (6 months post treatment)
Working Alliance Inventory (WAI)
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.
Time frame: Change from Baseline to Follow-up (6 months post treatment)
Psychological Distance Scaling Task (PDST)
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.
Time frame: Change from Baseline to Follow-up (6 months post treatment)
Plan to share: No
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