Cognitive Behavioral Therapy (CBT) Study Evaluating the Updating of Persecutory Beliefs

Vanderbilt University Medical Center62 enrolled

Overview

The purpose of this study is to examine how Bayesian belief updating changes throughout psychotherapeutic treatment for persecutory delusions. Specifically, individuals with a psychotic disorder diagnosis who endorse both a current persecutory delusion with strong conviction and significant worry will be recruited and randomized to receive either a CBT-based worry intervention for persecutory delusions or an active control condition (befriending therapy). The investigators will examine: 1) whether belief updating parameters change as delusion severity changes, 2) whether CBT contributes to greater change in belief updating parameters than befriending therapy, and 3) whether neural correlates of belief updating parameters, as measured using functional magnetic resonance imaging (fMRI), predict treatment response.

Study Type

INTERVENTIONAL

Allocation

RANDOMIZED

Purpose

TREATMENT

Masking

SINGLE

Enrollment

Conditions

Schizophrenia; Psychosis Persecutory Delusion

Interventions

Eligibility

Sex: ALLMin age: 18 YearsMax age: 65 Years

Medical Language ↔ Plain English

Inclusion Criteria: 1. Men and women age 18 - 65. 2. Communicative in English. 3. Premorbid Intelligence \>79 (WTAR) 4. Provide voluntary, written informed consent. 5. Physically healthy by medical history. 6. Weight \<300 lbs 7. Stable medication regimen over at least the past two weeks, including the use of either an oral or intramuscular administration of an antipsychotic medication. 8. Diagnosis of a non-affective psychotic disorder (schizophrenia, schizoaffective disorder, schizophreniform disorder, delusional disorder, brief psychotic disorder, psychosis NOS) confirmed by Structured Clinical Interview for Diagnostic and Statistical Manual (DSM)-5 (SCID) or diagnostic interview with a trained clinician. 9. A persecutory delusion scoring at least a 3 on the conviction scale of the Psychotic Symptoms Rating Scale (PSYRATS) that had persisted for at least two weeks and that was not considered the direct result of substance use 10. A clinically significant level of worry, as shown by a score of at least 44 on the Penn State Worry Questionnaire (PSWQ). Exclusion Criteria: 1. Age less than 18 or greater than 65. 2. Not communicative in English. 3. Premorbid IQ \< 79 (WTAR) 4. Unable to provide written informed consent. 5. Current medical or neurological illness. 6. History of severe head trauma. 7. Weight \>300 lbs 8. Primary diagnosis of alcohol or substance use disorder or personality disorder 9. Conditions that preclude fMRI scanning (as defined in the fMRI Screening Form) 10. Subjects who are actively involved with individual cognitive therapy (Past experience with individual therapy is not an exclusion)

Outcomes

Primary Outcomes

Computational Parameters of Belief Updating as Measured During a Probabilistic Reversal Learning Task

change in computational parameters after intervention

Time frame: Baseline, 4 weeks, 8 weeks, 24 weeks

Change in Delusion Severity Utilizing the Change in Psychotic Symptoms Rating Scale (PSYRATS)

The change in the Delusions subscale total of the Psychotic Symptoms Rating Scale (PSYRATS) from Baseline to Week 24. The Delusions subscale is a composite score of 6 items each rated from 0-4 with 4 indicating more severe symptomology. The Delusions subscale has a possible range of 0-24.

Time frame: Baseline, 4 weeks, 8 weeks, 24 weeks

Change in Neural Correlates of Belief Updating Parameters

Change in blood oxygen dependent level (BOLD) signal after intervention

Time frame: Baseline, 8 weeks

Secondary Outcomes

Baseline Neural Predictors of Treatment Response

BOLD signal during belief updating task at baseline predicting treatment response

Time frame: Baseline

Resting-State Predictors of Treatment Response

resting-state connectivity of functional networks predicting treatment response