Verbal memory impairments in mood disorders and psychotic disorders: A systematic review of comparative studies

Neuropsychological performance in women at risk of postpartum depression and postpartum psychosis

PURPOSE

While neuropsychological deficits are commonly observed in affective and psychotic disorders, this remains unexplored in these disorders when they occur during pregnancy and the postpartum period.

METHODS

A neuropsychological test battery was administered to women defined at risk of postpartum depression (PD, N = 53) because having either a current or past diagnosis of major depressive disorder, women at risk of postpartum psychosis (PP, N = 43) because of a diagnosis of bipolar disorder or schizoaffective disorder and/or a previous episode of PP and women not at risk (NR, N = 48) in the third trimester of pregnancy. Generalized and specific cognitive abilities were compared between groups.

RESULTS

Women at risk of PP presented worse executive functions and processing speed compared to NR and worse performance compared to women at risk of PD across all cognitive domains. In addition, women at risk of PP who developed a psychiatric relapse in the first four weeks post-partum showed worse verbal learning and memory, visual memory, executive functions and processing speed in pregnancy compared to NR, whereas women at risk of PP who remained well presented neuropsychological performance that was intermediate between that of the women NR and those at risk of PP who developed symptoms. There were no differences in performance between women at risk of PD and the NR women, even if 31 women at risk of PD presented depressive symptoms at the time of cognitive assessment.

CONCLUSIONS

Our findings in women at risk of PP align with neuropsychological findings in individuals with, or at risk of psychosis unrelated to pregnancy. In addition, initial evidence that women at risk of PP who develop a psychiatric relapse in the postpartum show a particularly poor neuropsychological performance in pregnancy suggests that this could be considered part of a phenotype for the disease and help guiding future preventive strategies in this clinical population. In women at risk of PD, the presence of depressive symptoms did not influence cognitive performance.

Using virtual reality to improve verbal episodic memory in schizophrenia: A proof-of-concept trial

Background

Schizophrenia is associated with impairments in verbal episodic memory. Strategy for Semantic Association Memory (SESAME) training represents a promising cognitive remediation program to improve verbal episodic memory. Virtual reality (VR) may be a novel tool to increase the ecological validity and transfer of learned skills of traditional cognitive remediation programs. The present proof-of-concept study aimed to assess the feasibility, acceptability, and preliminary efficacy of a VR-based cognitive remediation module inspired by SESAME principles to improve the use of verbal episodic memory strategies in schizophrenia.

Methods

Thirty individuals with schizophrenia/schizoaffective disorder completed this study. Participants were randomized to either a VR-based verbal episodic memory training condition inspired by SESAME principles (intervention group) or an active control condition (control group). In the training condition, a coach taught semantic encoding strategies (active rehearsal and semantic clustering) to help participants remember restaurant orders in VR. In the active control condition, participants completed visuospatial puzzles in VR. Attrition rate, participant experience ratings, and cybersickness questionnaires were used to assess feasibility and acceptability. Trial 1 of the Hopkins Verbal Learning Test - Revised was administered pre- and post-intervention to assess preliminary efficacy.

Results

Feasibility was demonstrated by a low attrition rate (5.88 %), and acceptability was demonstrated by limited cybersickness and high levels of enjoyment. Although the increase in the number of semantic clusters used following the module did not reach conventional levels of statistical significance in the intervention group, it demonstrated a notable trend with a medium effect size (t = 1.48, p = 0.15, d = 0.54), in contrast to the control group where it remained stable (t = 0.36, p = 0.72, d = 0.13). These findings were similar for the semantic clustering ratio in the intervention (t = 1.61, p = 0.12, d = 0.59) and control (t = 0.36, p = 0.72, d = 0.13) groups. There was no significant change in the number of recalled words in either group following VR immersion.

Discussion

This VR intervention was feasible, acceptable, and may be useful for improving the use of semantic encoding strategies. These findings support the use of more ecological approaches for the treatment of cognitive impairments in schizophrenia, such as VR-based cognitive remediation.

Revisiting Cognitive Deficits in Outpatients with Psychotic Disorders: A Transdiagnostic Comparison of Cognitive Performance While Accounting for Putative Confounding Factors

Recent research suggests that cognitive deficits in individuals with psychotic disorders could be overestimated because poor cognitive test performance is partly attributable to non-cognitive factors. To further test this, we included non-hospitalized individuals with psychotic disorders (PSY, n = 38), individuals with attenuated psychotic symptoms (n = 40), individuals with obsessive-compulsive disorders (n = 39), and healthy controls (n = 38). Relevant cognitive domains were assessed using the MATRICS Consensus Cognitive Battery. Putative confounding non-cognitive factors-heart rate, self-reported stress, negative affect, performance-related beliefs, and actigraphy-derived sleep-were assessed before cognitive testing. A multivariate analysis of covariance was calculated to examine group differences in cognitive performance while controlling for non-cognitive factors. PSY showed decreased test performance in graphomotor speed, attention, and verbal tasks compared to the other groups, whereas non-verbal/visual-spatial tasks were unimpaired. After accounting for non-cognitive factors, group differences diminished in verbal learning, whereas differences in the other domains remained significant. Against our hypotheses, the present findings indicate that some cognitive deficits in PSY cannot be attributed to momentary confounding factors.