Neuropsychological functioning in early and chronic stages of schizophrenia and psychotic bipolar disorder

Abstract

Background: Neuropsychological impairment is common in schizophrenia and psychotic bipolar disorder. It has been hypothesized that the pathways leading to impairment differ between disorders. Cognitive impairment in schizophrenia is believed to result largely from atypical neurodevelopment, whereas bipolar disorder is increasingly conceptualized as a neuroprogressive disorder. The current investigation tested several key predictions of this hypothesis. Methods: Current neuropsychological functioning and estimated premorbid intellectual ability were assessed in healthy individuals (n=260) and a large, cross-sectional sample of individuals in the early and chronic stages of psychosis (n=410). We tested the following hypotheses: 1) cognitive impairment is more severe in schizophrenia in the early stage of psychosis; and 2) cognitive decline between early and chronic stages is relatively greater in psychotic bipolar disorder. Additionally, individuals with psychosis were classified as neuropsychologically normal, deteriorated, and compromised (i.e. below average intellectual functioning) to determine if the frequencies of neuropsychologically compromised and deteriorated patients were higher in schizophrenia and psychotic bipolar disorder, respectively. Results: Neuropsychological impairment in the early stage of psychosis was more severe in schizophrenia. Psychotic bipolar disorder was not associated with relatively greater cognitive decline between illness stages. The frequency of neuropsychologically compromised patients was higher in schizophrenia; however, substantial portions of both schizophrenia and psychotic bipolar disorder patients were classified as neuropsychologically compromised and deteriorated.

Insula functional connectivity in schizophrenia

“…One subject was missing a positive scale score, so the average PANSS positive score across all schizophrenia participants was used for that subject. All individuals were administered the Screen for Cognitive Impairment in Psychiatry (SCIP), a brief (10-15 minute) measure of immediate and delayed verbal memory, verbal fluency, working memory and processing speed (for description of SCIP see (Menkes et al, 2018)). Scores from each sub-test were z-scored based on published norms (Purdon, 2005) and summed as a measure of cognitive ability.…”

Do sleep disturbances contribute to cognitive impairments in schizophrenia spectrum and bipolar disorders?

“…Today, a large body of literature demonstrates marked impairments in multiple cognitive domains in schizophrenia. Attention, memory and executive functions are among the most severely impaired domains Heinrichs, 2005;Heinrichs & Zakzanis, 1998;Menkes, Armstrong, Blackford, Heckers, & Woodward, 2019). Also in bipolar disorder cognitive impairments are widely reported, particularly in many of the same cognitive domains as in schizophrenia; i.e.…”

Cognitive Heterogeneity across Schizophrenia and Bipolar Disorder: A Cluster Analysis of Intellectual Trajectories

“…A meta-analysis of studies that included participants with schizophrenia and bipolar disorder in direct comparisons concluded that significant premorbid Cognitive subgroups in severe mental illness deficits are present in schizophrenia and that both disorders are characterized by cognitive decline after illness onset, with larger impairments in schizophrenia (Trotta, Murray, & MacCabe., 2015). Indeed, there is evidence for neurodevelopmental and neuroprogressive cognitive trajectories in both disorders (Menkes, Armstrong, Balckford, Heckers, & Woodward, 2019).…”