Improving Visual Attention in Schizophrenia

Improving Visual Attention to Social Stimuli in Individuals With Schizophrenia

This study investigates whether visual attention can be improved in individuals with schizophrenia by stimulating the brain via transcranial Direct Current Stimulation (tDCS).

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