Cognitive Deficits in Schizophrenia and Alcoholism: A Review of the Evidence and Findings on the Effects of Treatment on Cognitive Functioning in Patients With Dual Diagnoses

The role of cognitive functioning in the relationship between childhood trauma and a mixed phenotype of affective-anxious-psychotic symptoms in psychotic disorders

Cognitive impairments in patients with psychotic disorder have been associated with poor functioning and increased symptom severity. Furthermore, childhood trauma (CT) exposure has been associated with worse cognitive functioning as well as co-occurrence of affective-anxious-psychosis symptoms or a 'mixed phenotype of psychopathology' (MP), which in turn is associated with greater symptom severity, and poor functioning. This study aims to evaluate if cognition could be associated with CT/MP. 532 patients with non-affective psychotic patients were assessed on CT, symptom profile, cognition, functioning, and symptom severity at baseline and 3 and 6-year follow-up. Four subgroups were made according to trauma exposure (CT- or CT+) and presence of a mixed phenotype (MP- or MP+): CT-/MP (n=272), CT-/MP+ (n=157), CT+/MP- (n=49), and CT+/MP+ (n=54). Mixed-effects multilevel regression, linear regression, and Tobit analyses were performed. Patients with both CT and MP showed lower verbal learning and memory than CT-/MP+ individuals (p<0.001). No other significant differences were found among the 4 subgroups. No cognitive decline was found at follow-up, neither in the CT+/MP- nor in CT-/MP- group. Lower cognition was not associated with increased symptom severity or poor functioning at follow-up, neither in the CT+/MP- nor in CT-/MP- group. Although cognitive impairments and CT may be related to clinical or functional features of psychotic disorder, and cognitive functioning could be affected by CT exposure, cognition does not discriminate subgroups of patients stratified by CT exposure and MP.

Task and resting-state fMRI studies in first-episode schizophrenia: A systematic review

In the last two decades there has been an increase on task and resting-state functional Magnetic Resonance Imaging (fMRI) studies that explore the brain's functional changes in schizophrenia. However, it remains unclear as to whether the brain's functional changes during the resting state are sensitive to the same brain regions during task fMRI. Therefore, we conducted a systematic literature search of task and resting-state fMRI studies that investigated brain pathological changes in first-episode schizophrenia (Fleischhacker et al.). Nineteen studies met the inclusion criteria; seven were resting state fMRI studies with 371 FES patients and 363 healthy controls and twelve were task fMRI studies with 235 FES patients and 291 healthy controls. We found overlapping task and resting-state fMRI abnormalities in the prefrontal regions, including the dorsal lateral prefrontal cortex, the orbital frontal cortex and the temporal lobe, especially in the left superior temporal gyrus (STG). The findings of this systematic review support the frontotemporal hypothesis of schizophrenia, and the disruption in prefrontal and STG might represent the pathophysiology of schizophrenia disorder at a relatively early stage.

Broad spectrum psychiatric comorbidity is associated with better executive functioning in an inpatient sample of individuals with schizophrenia

BACKGROUND

Individuals with schizophrenia exhibit cognitive deficits but whether these deficits are exacerbated by broad spectrum psychiatric comorbidity (i.e., comorbidity that is inclusive of disorders from different diagnostic categories) is unclear. A broad spectrum approach to psychiatric comorbidity is an ecologically valid way to capture the diagnostic heterogeneity inherent in psychiatric presentations.

OBJECTIVE

This study compared the attention, working memory, processing speed, and executive functioning of individuals with schizophrenia only relative to individuals with schizophrenia and broad spectrum psychiatric comorbidity.

METHOD

Archival patient neuropsychological test data were obtained for a sample of patients with schizophrenia only (n=30) and a sample of patients with schizophrenia and psychiatric comorbidity (n=33). Relevant tests were used to form composite indices for the cognitive domains of attention, working memory, speed of processing, and executive functioning.

RESULTS

Unexpectedly, individuals with schizophrenia and psychiatric comorbidity had significantly better executive functioning than individuals with schizophrenia only. There were no other significant differences.

CONCLUSIONS

A broad spectrum approach to psychiatric comorbidity can help to account for differences in the executive functioning of individuals with schizophrenia. In clinical settings, individuals with schizophrenia and psychiatric comorbidity may benefit from intervention strategies that capitalize on their relatively higher executive functioning.