Theory of mind and executive functions in schizophrenia and bipolar disorder: A cross-diagnostic latent class analysis for identification of neuropsychological subtypes

Cognitive Impairment in Bipolar Disorder: Treatment and Prevention Strategies

Over the last decade, there has been a growing appreciation of the importance of identifying and treating cognitive impairment associated with bipolar disorder, since it persists in remission periods. Evidence indicates that neurocognitive dysfunction may significantly influence patients' psychosocial outcomes. An ever-increasing body of research seeks to achieve a better understanding of potential moderators contributing to cognitive impairment in bipolar disorder in order to develop prevention strategies and effective treatments. This review provides an overview of the available data from studies examining treatments for cognitive dysfunction in bipolar disorder as well as potential novel treatments, from both pharmacological and psychological perspectives. All these data encourage the development of further studies to find effective strategies to prevent and treat cognitive impairment associated with bipolar disorder. These efforts may ultimately lead to an improvement of psychosocial functioning in these patients.

Social cognition in first-degree relatives of patients with bipolar disorder: A meta-analysis

Cognitive impairment is evident euthymic patients with bipolar disorder (BP) and in their first-degree relatives (BP-Rel). Increasing evidence suggests that BP is also associated with social cognitive impairment. It is important to establish whether social cognitive impairment is also evident in BP-Rel. A novel meta-analysis of theory of mind (ToM) and facial emotion recognition in BP-Rel including 16 studies (728 first-degree relatives of patients with BP and 865 healthy controls) was conducted. ToM (d=0.34, CI=0.16-0.52) was significantly impaired in BP-Rel. The effect size for the difference between BP-Rel and healthy controls was smaller for facial emotion recognition (d=0.17, CI=0.16-0.29) and could be nonsignificant after the effect of publication bias was taken into account. First-degree relatives of patients with BP underperform healthy subjects in social cognitive abilities, particularly in ToM. However, the effect size for between-group difference is small. ToM impairment might be a vulnerability marker of BP.

Differences in cognitive impairment between schizophrenia and bipolar disorder: Considering the role of heterogeneity

Schizophrenia is associated with significant cognitive impairment. Bipolar disorder (BD) also presents with cognitive deficits that are similar to, albeit less severe, than those reported in schizophrenia. There has been controversy over whether selective deficits in social cognition or developmental trajectory of cognitive deficits can distinguish schizophrenia from BD. Also, available studies have not generally considered the potential effect of cognitive heterogeneity within the two disorders on between-group differences. The current review examines the evidence on the specificity of social cognitive deficits and early neurocognitive impairment to schizophrenia and explores the overall outcome of studies investigating within and cross-diagnosis cognitive heterogeneity in schizophrenia and BD. Current evidence does not support the specificity of social cognitive impairment to schizophrenia. Available studies also suggest that cognitive impairment in premorbid and early stages is evident not only in schizophrenia but also in many BD patients. Both schizophrenia and BD have a number of cognitive subgroups, including severe impairment, good functioning, and one or more selective or modest impairment clusters. While both disorders are represented in each cognitive subgroup, there are significant cross-diagnostic differences regarding prevalences of individuals belonging to the severe impairment and good functioning subgroups. Individuals with schizophrenia are much more likely to exhibit severe cognitive impairment than individuals with BD and good cognitive functioning is more often observed in BD patients than schizophrenia patients. Further identification of the neurobiological and genetic characteristics of the cognitive subgroups in major psychoses can improve the validity of diagnostic systems and can advance the development of personalized management approaches, including cognitive remediation.