Stimulating the Social Brain

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.

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)