We used a set of measures to assess psychiatric symptoms and cognitive functioning, which included the Schizotypal Personality Questionnaire (SPQ; Raine, 1991 (link)), The Brief Assessment of Cognition in Schizophrenia; (BACS; Keefe et al., 2004 (link)), The Brief Psychiatric Rating Scale (BPRS; Overall & Gorham, 1962 ), and The Sensory Gating Inventory (SGI; Bailey et al., 2021 (link); Hetrick et al., 2012 (link)). Out of a variety of clinical assessments administered as a part of the pHCP (Demro et al., 2021 (link)), we chose these as they provide measures of overall psychiatric symptom levels, schizotypy, and cognitive functions, and previous work has found relationships between these factors and visual dysfunction in people with psychotic disorders (Schmack et al., 2015 (link); Weilnhammer et al., 2020 (link); Xiao et al., 2018 (link)). These measures were collected for participants in all three groups (unlike other measures that were collected only from PwPP). In addition to the four primary measures mentioned here, we also chose to include the cognitive-perceptual subscale from the SPQ (SPQ-CP) and a disorganization factor from the BPRS (BPRS-D; Wilson & Sponheim, 2014 (link)), as they are particularly relevant to our analyses and hypotheses.
To investigate relationships between symptom severity and percept switch rate, we first correlated individual symptom measures with average switch rates across all three groups. We used Spearman rank correlations to avoid assuming linear relationships. Data from re-test sessions were excluded from these correlations, as Spearman correlations assume independent data points.
To investigate relationships between symptom severity and percept switch rate, we first correlated individual symptom measures with average switch rates across all three groups. We used Spearman rank correlations to avoid assuming linear relationships. Data from re-test sessions were excluded from these correlations, as Spearman correlations assume independent data points.
