The Efficacy of Neural Stimulation in Individuals With Schizophrenia

Not Applicable

Completed

Conditions: Schizo Affective Disorder
Schizophrenia

Interventions: Device: tDCS

Registration Number: NCT05746494

Lead Sponsor: The University of Texas at Dallas

Brief Summary: 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.

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.

Recruitment & Eligibility

Status: COMPLETED

Sex: All

Target Recruitment: 50

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 & Design

Study Type: INTERVENTIONAL

Study Design: CROSSOVER

Arm && Interventions

Group	Intervention	Description
Active anodal tDCS first, then Sham tDCS	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.
Sham tDCS first, then Active anodal tDCS	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.

Primary Outcome Measures

Name	Time	Method
The State Social Paranoia Scale (SSPS)	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.
Ecological Momentary Assessment (EMA)-Based Paranoia	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.
Birchwood Social Functioning Scale (SFS)	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).
Ecological Momentary Assessment (EMA)-Based Social Functioning	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 Outcome Measures

Name	Time	Method
The Trustworthiness Task	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.
The Scrambled-sentences Task (SST)	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).
The Ambiguous Intentions Hostility Questionnaire (AIHQ)	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).
The Hostility Scale of the Personality Inventory for DSM-5 (PID-5-HS)	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.