Both unmedicated and medicated individuals with schizophrenia show impairments across a wide array of cognitive and reinforcement learning tasks

Abstract

Background Schizophrenia is a disorder characterized by pervasive deficits in cognitive functioning. However, few well-powered studies have examined the degree to which cognitive performance is impaired even among individuals with schizophrenia not currently on antipsychotic medications using a wide range of cognitive and reinforcement learning measures derived from cognitive neuroscience. Such research is particularly needed in the domain of reinforcement learning, given the central role of dopamine in reinforcement learning, and the potential impact of antipsychotic medications on dopamine function. Methods The present study sought to fill this gap by examining healthy controls (N = 75), unmedicated (N = 48) and medicated (N = 148) individuals with schizophrenia. Participants were recruited across five sites as part of the CNTRaCS Consortium to complete tasks assessing processing speed, cognitive control, working memory, verbal learning, relational encoding and retrieval, visual integration and reinforcement learning. Results Individuals with schizophrenia who were not taking antipsychotic medications, as well as those taking antipsychotic medications, showed pervasive deficits across cognitive domains including reinforcement learning, processing speed, cognitive control, working memory, verbal learning and relational encoding and retrieval. Further, we found that chlorpromazine equivalency rates were significantly related to processing speed and working memory, while there were no significant relationships between anticholinergic load and performance on other tasks. Conclusions These findings add to a body of literature suggesting that cognitive deficits are an enduring aspect of schizophrenia, present in those off antipsychotic medications as well as those taking antipsychotic medications.

Impaired contour object perception in psychosis

“…Our behavioral data revealed poorer contour discrimination accuracy and lower (impaired) jitter thresholds among PwPP, especially those with schizophrenia. Previous studies have yielded mixed results with regard to difference in jitter thresholds during contour integration in psychosis, with some studies observing significant impairments relative to controls (Grove et al, 2018;Keane et al, 2012Keane et al, , 2016Pokorny, Lano, et al, 2021;Robol et al, 2013;Schallmo et al, 2013), and others finding no such difference (Moran et al, 2022;Silverstein et al, 2012Silverstein et al, , 2015. Our results provide evidence in favor of such an impairment in jittered contour discrimination thresholds among PwPP, especially individuals with schizophrenia, and support the notion of normative contour perception among biological relatives (Pokorny, Lano, et al, 2021;Schallmo et al, 2013).…”

“…schizophrenia showed significantly lower jitter thresholds compared to healthy controls (ANOVA, main effect of group; F (1, 62) = 4.69, p = 0.034) and participants with bipolar disorder (ANOVA, main effect of group; F (1, 47) = 5.55, p = 0.023; Figure 3C). Lower tolerance for orientation jitter during contour discrimination among PwPP, and especially individuals with schizophrenia, is consistent with impaired contour integration in these groups (Grove et al, 2018;Keane et al, 2012Keane et al, , 2016Moran et al, 2022;Pokorny, Lano, et al, 2021;Robol et al, 2013;Schallmo et al, 2013;Silverstein et al, 2012Silverstein et al, , 2015.…”

“…Less tolerance for jitter has been reported in people with psychotic disorders for both closed (Keane et al, 2016;Silverstein et al, 2012) and open contours (Robol et al, 2013;Schallmo et al, 2013). Others have reported decreased contour discrimination accuracy in psychosis, but no difference in jitter thresholds (Moran et al, 2022;Silverstein et al, 2015). Neuroimaging studies of contour and shape integration in schizophrenia have suggested abnormalities at various levels of the visual processing hierarchy (Keane et al, 2021;Pokorny, Espensen-Sturges, et al, 2021), including regions such as LOC (Silverstein et al, 2009(Silverstein et al, , 2015.…”

Early Recognition Method – Amplifying relapse management in community mental health care; a comprehensive study of the effects on relapse and readmission

“…This is not the case for patients with bipolar disorder (Ceylan et al, 2020). The impaired cognitive performance is seen in both medicated and un-medicated patients, although in some areas to a slightly lesser degree in un-medicated individuals, suggesting that the cognitive impairments are aspects of schizophrenia, rather than the result of medication (Moran et al, 2020). The cognitive impairments associated with schizophrenia includes a deficient explicit and intact implicit learning (Ceylan et al, 2020;Lynham et al, 2018).…”

Schizophrenia: Epidemiology, Causes, Neurobiology, Pathophysiology, and Treatment

“…Antipsychotic medication is known to induce cognitive decline as well as other side effects related to greater morbidity and mortality (Agbeli, 2020). Moran et. al.…”