The Efficacy of Neural Stimulation in Individuals With Schizophrenia

The purpose of this study is to understand the relationship between psychotic symptoms and social functioning in individuals with schizophrenia spectrum disorders. Our goal is to determine whether stimulating the brain using transcranial Direct Current Stimulation (tDCS) can improve symptoms and daily functioning.

Study Overview

• Status: Completed
• Conditions: Schizophrenia; Schizo Affective Disorder
• Intervention / Treatment: Device: tDCS

Detailed Description

Paranoid ideation is a common delusion experienced by individuals with schizophrenia spectrum disorders (SSD) that negatively impacts social interactions and quality of life. Therefore, efforts to reduce paranoid thinking via neuromodulation techniques [e.g., transcranial direct current stimulation (tDCS)] are in development, with amygdala-prefrontal cortex (PFC) circuits targeted as critical components of the neural mechanisms underlying paranoia.

This project aims to alleviate paranoia and improve social functioning in individuals with SSD by implementing tDCS to ventrolateral PFC. A double-blind, within-subjects, crossover design will be used to compare the effects of active vs. sham tDCS. Ecological Momentary Assessments (EMA) will also be utilized to quantify any delayed stimulation effects in daily social interactions.

• Study Type: Interventional
• Enrollment (Actual): 50
• Phase: Not Applicable

Contacts and Locations

Study Locations

• United States
  • Texas
    • Richardson, Texas, United States, 75080
      • The Unversity of Texas at Dallas

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 60 years (Adult)
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• Age = 18-64
• Diagnosed with schizophrenia or schizoaffective disorder
• Having current (in the past week) or recent (in the past month) paranoia

Exclusion Criteria:

• Presence or history of a pervasive developmental disorder or mental retardation as defined by IQ < 70
• Presence or history of neurological or medical disorders that contraindicate neural stimulation (e.g. presence or history of epilepsy, seizures, etc.)
• Demonstrating sensory limitations, including uncorrectable visual or hearing impairments that interfere with assessment
• History of electroconvulsive therapy
• Lack of proficiency in English
• Substance use disorder not in remission in the past 6 months
• Any implanted devices such as pace maker, neurostimulator
• Pregnancy

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Basic Science
• Allocation: Randomized
• Interventional Model: Crossover Assignment
• Masking: Double

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Active anodal tDCS first, then Sham tDCS; Active anodal tDCS (40 minutes; divided into two 20-minutes sessions) followed by behavioral testing; Washout (about 1 week); sham stimulation (40 minutes; divided into two 20-minutes sessions) followed by behavioral testing.	Device: tDCS; active anodal tDCS and sham tDCS
Sham Comparator: Sham tDCS first, then Active anodal tDCS; Sham tDCS (40 minutes; divided into two 20-minutes sessions) followed by behavioral testing; Washout (about 1 week); Active anodal tDCS (40 minutes; divided into two 20-minutes sessions) followed by behavioral testing Intervention.	Device: tDCS; active anodal tDCS and sham tDCS

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
The State Social Paranoia Scale (SSPS)	Paranoid ideation was measured by the State Social Paranoia Scale (SSPS). Participants indicated how much they agree with each of 20 statements (e.g., "Someone was hostile towards me", "Someone was trying to isolate me") using a 5-point Likert scale (1 = do not agree, 5 = totally agree). Scores range from 20-100, and higher scores represent higher state paranoid ideation.	The assessment was completed before the stimulation and 30 minutes after completion of the active/sham stimulation
Ecological Momentary Assessment (EMA)-Based Paranoia	Paranoid ideation was measured by Ecological Momentary Assessment (EMA), which involved questions about feelings of paranoia in daily life. The paranoia-related question is as follows: "Since the past alarm, how much have you had thoughts that you really can't trust other people?" The score for this item ranges from 1 to 7, with a higher score indicating a higher level of paranoid thinking.	Change in daily paranoia feelings was assessed from the pre-stimulation EMA period (7 days before the stimulation visit) to the post-stimulation EMA period (7 days after the stimulation visit)
Birchwood Social Functioning Scale (SFS)	Social functioning was measured by the Birchwood Social Functioning Scale (SFS). This scale measures social adjustment based on self-reports (4- or 5-point scales), with higher total scores indicating better social functioning (range = 0-223).	The assessment was completed 30 minutes after completion of the active/sham stimulation
Ecological Momentary Assessment (EMA)-Based Social Functioning	Social functioning was measured by Ecological Momentary Assessment (EMA) (i.e., questions about daily interactions with others). Two subscores were generated: social interaction frequency (score ranges from 0-5, a higher score indicates more frequent social interactions), social interaction motivation and experience (scores range from 1-7, a higher score indicates higher motivations to interact with others and better experiences during these interactions).	Change in daily interactions was assessed from the pre-stimulation EMA period (7 days before the stimulation visit) to the post-stimulation EMA period (7 days after the stimulation visit)

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
The Trustworthiness Task	Paranoid ideation was measured by the Trustworthiness Task. This task requires participants to indicate how much they trust each of 60 grayscale facial stimuli along a 7-point Likert scale (-3 = very untrustworthy, 3 = very trustworthy). Total scores were calculated by averaging across responses and hence varied from -3 to +3, with higher values indicating a greater tendency to trust others.	The assessment was completed 30 minutes after completion of the active/sham stimulation
The Scrambled-sentences Task (SST)	Paranoid ideation was measured by the Scrambled-sentences task (SST). This task measures the level of paranoia by asking participants to create sentences of either paranoid or nonparanoid meanings, with a greater percentage indicating a higher level of paranoid interpretation bias (range = 0-1).	The assessment was completed 30 minutes after completion of the active/sham stimulation
The Ambiguous Intentions Hostility Questionnaire (AIHQ)	Paranoid ideation was measured by the Ambiguous Intentions Hostility Questionnaire (AIHQ). Three subscores were generated: AIHQ (blame) (ranging from 3-16, with a higher score indicating a higher level of blaming tendency), AIHQ (hostility) (ranging from 1-5, with a higher score indicating a higher level of hostility), AIHQ (aggression) (ranging from 1-5, with a higher score indicating a higher level of aggression).	The assessment was completed 30 minutes after completion of the active/sham stimulation
The Hostility Scale of the Personality Inventory for DSM-5 (PID-5-HS)	Paranoid ideation was measured by the Hostility Scale of the Personality Inventory for DSM-5 (PID-5-HS). PID-5-HS contains 10 self-report items assessing pathological hostility. A total score (range from 0-30) was generated to reflect overall hostility level, with higher total scores indicating more hostility.	The assessment was completed 30 minutes after completion of the active/sham stimulation

Collaborators and Investigators

• Sponsor: The University of Texas at Dallas

Study record dates

Study Major Dates

• Study Start (Actual): November 21, 2022
• Primary Completion (Actual): August 1, 2024
• Study Completion (Actual): August 1, 2024

Study Registration Dates

• First Submitted: February 2, 2023
• First Submitted That Met QC Criteria: February 24, 2023
• First Posted (Actual): February 27, 2023

Study Record Updates

• Last Update Posted (Actual): March 25, 2025
• Last Update Submitted That Met QC Criteria: February 3, 2025
• Last Verified: February 1, 2025

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Schizophrenia Spectrum and Other Psychotic Disorders; Mental Disorders; Schizophrenia; Psychotic Disorders; Mood Disorders
• Other Study ID Numbers: 22-630

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: Yes
• product manufactured in and exported from the U.S.: Yes