Healthy Adults
Conditions
Brief summary
This study investigates whether the way in which individuals process social stimuli can be altered, and specifically, whether feelings of paranoia and suspiciousness can be reduced by stimulating the brain's regulatory regions via transcranial Direct Current Stimulation (tDCS).
Detailed description
Although paranoid ideation is typically associated with severe mental illnesses such as schizophrenia or bipolar disorder, 10-15% of individuals in the general population report experiencing paranoid thoughts on a regular basis. These individuals who are high in sub-clinical paranoia can show impaired work and social functioning as compared to individuals low in sub-clinical paranoia. The wide spread prevalence and negative functional impact of heightened paranoia reinforces the need to develop interventions that may help to reduce problematic patterns of paranoid thinking in both healthy individuals and those with mental illness. Transcranial Direct Current Stimulation (tDCS) is a form of noninvasive neurostimulation which has been proposed as a therapeutic procedure in numerous psychiatric conditions. TDCS therefore may be a promising therapeutic technique for reducing symptoms of psychosis, and specifically paranoia. This study will compare experiences of paranoid ideation in individuals who are high in sub-clinical paranoia across two conditions: active anodal tDCS and sham tDCS.
Interventions
DEVICEactive anodal tDCS
active anodal tDCS with behavioral tasks and self-report measures to assess paranoid ideation
DEVICEsham tDCS
sham tDCS with behavioral tasks and self-report measures to assess paranoid ideation
Sponsors
The University of Texas at Dallas
Study design
Allocation
RANDOMIZED
Intervention model
CROSSOVER
Primary purpose
BASIC_SCIENCE
Masking
DOUBLE (Subject, Outcomes Assessor)
Intervention model description
Participants will complete active and sham simulation sessions in a randomized, counterbalanced order approximately one week apart.
Eligibility
Sex/Gender
ALL
Age
18 Years to 35 Years
Healthy volunteers
Yes
Inclusion criteria
* between the ages of 18 ad 35 * previous classification as being high in sub-clinical paranoia
Exclusion criteria
* diagnosis of mental illness * use of psychotropic medication * Presence or history of medical, cardiac, or neurological disorders that may affect brain function (e.g., cardiac disease, endocrine disorders, renal disease, pulmonary disease, history of seizures or head trauma with unconsciousness for a period of 15 minutes or greater or CNS tumors) * Presence of sensory limitation including visual (e.g., blindness, glaucoma, vision uncorrectable to 20/40) or hearing (e.g. hearing loss) impairments that interfere with assessment * Not proficient in English * Contraindications for tDCS (e.g., pregnancy or implanted devices such as pace maker)
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Change in General Paranoid Ideation for Active vs. Sham Simulation | Paranoid ideation will be assessed 30 minutes after completion of the active/sham stimulation | Level of paranoid ideation will be assessed with the self-report Paranoia Scale (PS; Fenigstein & Vanable, 1992) both before and after tDCS to assess changes related to tDCS. The PS is a self-report measure designed to assess sub-clinical paranoid thought. Scores range from 20-100 with higher scores indicating higher levels of paranoia. The amount of pre-post change (i.e. PS score assessed before stimulation minus score after stimulation) is the primary value of interest and will be compared between active and sham stimulation. Improvements in paranoia will be indicated by positive values. |
| Change in Change in Social Paranoia for Active vs. Sham Simulation | Paranoid ideation will be assessed 30 minutes after completion of the active/sham stimulation | Level of paranoid ideation will be assessed with the persecution subscale of the State Social Paranoia Scale (SSPS: Freeman et al., 2007) both before and after tDCS to assess changes related to tDCS. The SSPS is a psychometrically sound 20-item self- report measure assessing current levels of paranoid, positive, and neutral thinking about others. Ten items comprise the persecution subscale, and scores on this subscale range from 10-50 with higher scores indicating greater paranoia. The amount of pre-post change (i.e.SSPS score before stimulation minus SSPS score after stimulation) will be compared between active and sham stimulation. Positive values indicate reductions in paranoia after stimulation. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Trustworthiness Task Score for Active vs. Sham Stimulation | assessed 30 minutes after completion of the active/sham stimulation | Participants will complete the Trustworthiness Task (Adolphs, Tranel, & Damasio, 1998), which asks individuals to view 42 images of others and rate their level of trustworthiness on a scale from -3 to 3. Scores range from -126 to 126. Higher scores indicate greater perceptions of trustworthiness. Mean ratings following each stimulation type (active vs. sham) are calculated. |
| Penn Emotion Recognition Test for Active vs. Sham Stimulation | assessed 30 minutes after completion of the active/sham stimulation | The Emotion Recognition 40 (ER-40; Kohler, Turner, Bilker, Brinsinger, Siegel, Kanes... Gur, 2003) is a standardized, computer administered measure of facial affect recognition ability. It includes 40 color photographs of faces expressing 4 basic emotions (i.e. happiness, sadness, anger or fear) and neutral expressions. Participants view one face at a time and are asked to choose the correct emotion for each face. Scores range from 0-40 with higher scores indicating better accuracy. Mean performance following each stimulation type (active vs. sham) are calculated. |
Countries
United States
Participant flow
Participants by arm
| Arm | Count |
|---|---|
| Active Anodal tDCS, Then Sham tDCS Active anodal tDCS followed by behavioral testing; one week later, sham tDCS followed by behavioral testing
active anodal tDCS: active anodal tDCS with behavioral tasks and self-report measures to assess paranoid ideation
sham tDCS: sham tDCS with behavioral tasks and self-report measures to assess paranoid ideation | 20 |
| Sham tDCS, Then Active Anodal tDCS Sham tDCS followed by behavioral testing; one week later, active anodal tDCS followed by behavioral testing.
active anodal tDCS: active anodal tDCS with behavioral tasks and self-report measures to assess paranoid ideation
sham tDCS: sham tDCS with behavioral tasks and self-report measures to assess paranoid ideation | 20 |
| Total | 40 |
Baseline characteristics
| Characteristic | Active Anodal tDCS, Then Sham tDCS | Sham tDCS, Then Active Anodal tDCS | Total |
|---|---|---|---|
| Age, Continuous | 20.7 years STANDARD_DEVIATION 2.3 | 19.6 years STANDARD_DEVIATION 1.98 | 20.15 years STANDARD_DEVIATION 2.19 |
| Ethnicity (NIH/OMB) Hispanic or Latino | 5 Participants | 6 Participants | 11 Participants |
| Ethnicity (NIH/OMB) Not Hispanic or Latino | 15 Participants | 14 Participants | 29 Participants |
| Ethnicity (NIH/OMB) Unknown or Not Reported | 0 Participants | 0 Participants | 0 Participants |
| Race (NIH/OMB) American Indian or Alaska Native | 0 Participants | 0 Participants | 0 Participants |
| Race (NIH/OMB) Asian | 11 Participants | 10 Participants | 21 Participants |
| Race (NIH/OMB) Black or African American | 1 Participants | 0 Participants | 1 Participants |
| Race (NIH/OMB) More than one race | 2 Participants | 3 Participants | 5 Participants |
| Race (NIH/OMB) Native Hawaiian or Other Pacific Islander | 0 Participants | 0 Participants | 0 Participants |
| Race (NIH/OMB) Unknown or Not Reported | 0 Participants | 0 Participants | 0 Participants |
| Race (NIH/OMB) White | 6 Participants | 7 Participants | 13 Participants |
| Region of Enrollment United States | 20 participants | 20 participants | 40 participants |
| Sex: Female, Male Female | 12 Participants | 13 Participants | 25 Participants |
| Sex: Female, Male Male | 8 Participants | 7 Participants | 15 Participants |
Adverse events
| Event type | EG000 affected / at risk | EG001 affected / at risk |
|---|---|---|
| deaths Total, all-cause mortality | 0 / 40 | 0 / 40 |
| other Total, other adverse events | 0 / 40 | 0 / 40 |
| serious Total, serious adverse events | 0 / 40 | 0 / 40 |
Outcome results
Primary
Change in Change in Social Paranoia for Active vs. Sham Simulation
Level of paranoid ideation will be assessed with the persecution subscale of the State Social Paranoia Scale (SSPS: Freeman et al., 2007) both before and after tDCS to assess changes related to tDCS. The SSPS is a psychometrically sound 20-item self- report measure assessing current levels of paranoid, positive, and neutral thinking about others. Ten items comprise the persecution subscale, and scores on this subscale range from 10-50 with higher scores indicating greater paranoia. The amount of pre-post change (i.e.SSPS score before stimulation minus SSPS score after stimulation) will be compared between active and sham stimulation. Positive values indicate reductions in paranoia after stimulation.
Time frame: Paranoid ideation will be assessed 30 minutes after completion of the active/sham stimulation
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Active Stimulation | Change in Change in Social Paranoia for Active vs. Sham Simulation | .75 score on a scale | Standard Deviation 2.52 |
| Sham Stimulation | Change in Change in Social Paranoia for Active vs. Sham Simulation | .93 score on a scale | Standard Deviation 2.34 |
Primary
Change in General Paranoid Ideation for Active vs. Sham Simulation
Level of paranoid ideation will be assessed with the self-report Paranoia Scale (PS; Fenigstein & Vanable, 1992) both before and after tDCS to assess changes related to tDCS. The PS is a self-report measure designed to assess sub-clinical paranoid thought. Scores range from 20-100 with higher scores indicating higher levels of paranoia. The amount of pre-post change (i.e. PS score assessed before stimulation minus score after stimulation) is the primary value of interest and will be compared between active and sham stimulation. Improvements in paranoia will be indicated by positive values.
Time frame: Paranoid ideation will be assessed 30 minutes after completion of the active/sham stimulation
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Active Stimulation | Change in General Paranoid Ideation for Active vs. Sham Simulation | 1.60 score on a scale | Standard Deviation 3.11 |
| Sham Stimulation | Change in General Paranoid Ideation for Active vs. Sham Simulation | .73 score on a scale | Standard Deviation 3.8 |
Secondary
Penn Emotion Recognition Test for Active vs. Sham Stimulation
The Emotion Recognition 40 (ER-40; Kohler, Turner, Bilker, Brinsinger, Siegel, Kanes... Gur, 2003) is a standardized, computer administered measure of facial affect recognition ability. It includes 40 color photographs of faces expressing 4 basic emotions (i.e. happiness, sadness, anger or fear) and neutral expressions. Participants view one face at a time and are asked to choose the correct emotion for each face. Scores range from 0-40 with higher scores indicating better accuracy. Mean performance following each stimulation type (active vs. sham) are calculated.
Time frame: assessed 30 minutes after completion of the active/sham stimulation
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Active Stimulation | Penn Emotion Recognition Test for Active vs. Sham Stimulation | 35.05 score on a scale | Standard Deviation 2.39 |
| Sham Stimulation | Penn Emotion Recognition Test for Active vs. Sham Stimulation | 35.33 score on a scale | Standard Deviation 2.31 |
Secondary
Trustworthiness Task Score for Active vs. Sham Stimulation
Participants will complete the Trustworthiness Task (Adolphs, Tranel, & Damasio, 1998), which asks individuals to view 42 images of others and rate their level of trustworthiness on a scale from -3 to 3. Scores range from -126 to 126. Higher scores indicate greater perceptions of trustworthiness. Mean ratings following each stimulation type (active vs. sham) are calculated.
Time frame: assessed 30 minutes after completion of the active/sham stimulation
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Active Stimulation | Trustworthiness Task Score for Active vs. Sham Stimulation | -.14 score on a scale | Standard Deviation 0.64 |
| Sham Stimulation | Trustworthiness Task Score for Active vs. Sham Stimulation | -.14 score on a scale | Standard Deviation 0.6 |