Improving Visual Attention in Schizophrenia

Individuals with schizophrenia tend to display abnormal visual attention when performing
visual tasks, typically spending less time on salient features of the stimuli (e.g. core
facial features or body movement in social tasks), and instead focusing on idiosyncratic
features of an image or video. Poor visual attention in schizophrenia has been directly
linked to poorer social cognitive performance (e.g. recognizing emotional expressions or
social cues) which can impact an individual's day to day functioning.

Transcranial Direct Current Stimulation (tDCS) is a form of noninvasive neurostimulation
which has been proposed as a therapeutic procedure in numerous psychiatric disorders. TDCS in
schizophrenia has been demonstrated to improve a wide range of cognitive processes, and in
healthy adults, tDCS has been demonstrated to improve aspects of social cognition. TDCS thus
appears to be a promising therapeutic technique that may be useful for improving visual
attention in patients with schizophrenia, and potentially impact social cognitive performance
via an underlying mechanism tying the two. This study will compare visual performance in
individuals with schizophrenia across two conditions: active anodal tDCS and sham tDCS, while
also comparing between brain stimulation sites: rTPJ and dmPFC.

Inclusion Criteria:

- DSM-IV-TR or DSM-5 diagnosis of schizophrenia or schizoaffective disorder and
clinically stable (i.e. no hospitalizations) for at least 8 weeks prior to informed
consent and be on a stable medication regimen for at least 6 weeks with no dose
changes for a minimum of 2 weeks prior to informed consent.

Exclusion Criteria:

- The presence or history of a pervasive developmental disorder or mental retardation as
defined by a premorbid IQ < 70

- Presence or history of medical or neurological disorders in which neural stimulation
would be contraindicated (e.g. presence of epilepsy or history of seizures)

- Presence of sensory limitations, including visual or hearing impairments that
interfere with assessment

- History of electroconvulsive therapy

- Not proficient in English

- Presence of substance abuse in the past one month or dependence not in remission in
the past six months