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Completed

NCT Number: NCT05746494

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.

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Key information

Conditions

Schizophrenia Mental Disorders Psychotic Disorders Schizo Affective Disorder Schizophrenia Spectrum and Other Psychotic Disorders

Age range

18 year–64 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

The Unversity of Texas at Dallas

Richardson, Texas, 75080, United States

About this study

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.

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

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

Treatment and study plan

tDCS

Device

active anodal tDCS and sham tDCS

Primary outcomes

  1. The State Social Paranoia Scale (SSPS)

    Time frame: The assessment was completed before the stimulation and 30 minutes after completion of the active/sham stimulation

    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.

  2. Ecological Momentary Assessment (EMA)-Based Paranoia

    Time frame: 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)

    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.

  3. Birchwood Social Functioning Scale (SFS)

    Time frame: The assessment was completed 30 minutes after completion of the active/sham stimulation

    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).

  4. Ecological Momentary Assessment (EMA)-Based Social Functioning

    Time frame: 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)

    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).

Secondary outcomes

  1. The Trustworthiness Task

    Time frame: The assessment was completed 30 minutes after completion of the active/sham stimulation

    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.

  2. The Scrambled-sentences Task (SST)

    Time frame: The assessment was completed 30 minutes after completion of the active/sham stimulation

    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).

  3. The Ambiguous Intentions Hostility Questionnaire (AIHQ)

    Time frame: The assessment was completed 30 minutes after completion of the active/sham stimulation

    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).

  4. The Hostility Scale of the Personality Inventory for DSM-5 (PID-5-HS)

    Time frame: The assessment was completed 30 minutes after completion of the active/sham stimulation

    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.

Sponsors and collaborators

Lead sponsor

The University of Texas at Dallas

Other

Registry information

Important dates

Study start
2022
Primary completion
2024
Study completion
2024
First posted
Feb 27, 2023
Registry last updated
Feb 26, 2025

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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