Cognitive Impairment in Bipolar Disorder: An Overview

Emotional and cognitive conflict resolution and disruptive mood dysregulation disorder in adolescent offspring of parents diagnosed with major depressive disorder, bipolar disorder, and matched healthy controls

AIMS

Children of parents with mood disorders have an elevated risk for various psychopathologies. In this study rate of psychopathologies among adolescent offspring of parents with major depressive (MDDoff) and bipolar disorder (BDoff), including disruptive mood dysregulation disorder (DMDD) along with the offspring ability to resolve cognitive and emotional conflicts were evaluated.

METHOD

12-16 years old children of parents with MDD (n = 31, children= 36), BP (n = 20, children = 26) and controls (n = 25, children = 28) were enrolled. Children and parents were evaluated by using the Kiddie Schedule for Affective Disorders and Schizophrenia (K-SADS) and the Structured Clinical Interview for DSM-IV Axis I Disorders (SCID); respectively. The parents completed the Child Behavior Checklist (CBCL)-dysregulation profile. The Stroop test-TBAG form and emotional Stroop test were given out to evaluate conflict resolution ability.

RESULTS

The most common diagnoses among the whole sample were attention deficit and hyperactivity, separation anxiety and oppositional defiant disorders. Five cases (5.5%) of lifetime DMDD were found (three from MDDoff, the rest from BDoff). Completion times for the Stroop test-TBAG form were ranked as: BDoff > MDDoff > Hoff. In the emotional Stroop test, the BDoff responded significantly later and had significantly reduced correct responses.

CONCLUSION

Rates of lifetime DMDD were similar in the MDDoff and BDoff groups. BDoff may experience greater difficulties in resolving cognitive and emotional conflicts.

The Limits between Bipolar Disorder and Borderline Personality Disorder: A Review of the Evidence

Bipolar disorder and borderline personality disorder are among the most frequently diagnosed psychiatric conditions. However, the nosological aspects and diagnostic boundaries of both conditions have historically been the object of considerable controversy. The present paper critically analyzes this debate, in light of available evidence. Clinical and neurobiological differences between bipolar disorder and borderline personality disorder are discussed, as well as the factors possibly involved in the overlap between both conditions and the potential implications of this.

Epidemiology and burden of bipolar disorder in Africa: a systematic review of data from Africa

BACKGROUND

Bipolar disorder impacts negatively on the patient, the family, as well as the society. It taxes the health care services due to a combination of the illness with associated medical and psychiatric comorbidities. In Africa, unfortunately, knowledge of the epidemiology and burden of bipolar disorder is based mainly on studies from the USA and Europe. In this systematic review of literature from Africa, we highlight the epidemiology and burden of bipolar disorder.

METHODS

A systematic review of publications from Africa relating to the epidemiology and burden of bipolar disorder was conducted.

RESULT

Data from community surveys conducted in Nigeria and Ethiopia indicated a lifetime prevalence estimate of 0.1 % to 1.83 for bipolar disorder. Missed diagnosis rate of bipolar disorder was up to 36.2 %. In one study, 8.1 % of the males and 5.4 % of the females reported a previous suicide attempt. A study showed that up to 60 % of patients with bipolar disorder had at least one comorbidity. There were no reports on all-cause mortality and cost of illness.

CONCLUSION

Bipolar disorder is a major mental health problem in Africa. Scientific findings on bipolar disorder from Africa are consistent with the existing literature from other parts of the world. There still exists a dearth of high quality studies addressing the epidemiological, clinical, social, and economic burden of the disorder.

Cerebral Correlates of Abnormal Emotion Conflict Processing in Euthymic Bipolar Patients: A Functional MRI Study

BACKGROUND

Patients with bipolar disorder experience cognitive and emotional impairment that may persist even during the euthymic state of the disease. These persistent symptoms in bipolar patients (BP) may be characterized by disturbances of emotion regulation and related fronto-limbic brain circuitry. The present study aims to investigate the modulation of fronto-limbic activity and connectivity in BP by the processing of emotional conflict.

METHODS

Fourteen euthymic BP and 13 matched healthy subjects (HS) underwent functional magnetic resonance imaging (fMRI) while performing a word-face emotional Stroop task designed to dissociate the monitoring/generation of emotional conflict from its resolution. Functional connectivity was determined by means of psychophysiological interaction (PPI) approach.

RESULTS

Relative to HS, BP were slower to process incongruent stimuli, reflecting higher amount of behavioral interference during emotional Stroop. Furthermore, BP showed decreased activation of the right dorsolateral prefrontal cortex (DLPFC) during the monitoring and a lack of bilateral amygdala deactivation during the resolution of the emotional conflict. In addition, during conflict monitoring, BP showed abnormal positive connectivity between the right DLPFC and several regions of the default mode network.

CONCLUSIONS

Overall, our results highlighted dysfunctional processing of the emotion conflict in euthymic BP that may be subtended by abnormal activity and connectivity of the DLPFC during the conflict monitoring, which, in turn, leads to failure of amygdala deactivation during the resolution of the conflict. Emotional dysregulation in BP may be underpinned by a lack of top-down cognitive control and a difficulty to focus on the task due to persistent self-oriented attention.

Neurocognitive impairments among youth with pediatric bipolar disorder: a systematic review of neuropsychological research

BACKGROUND

Pediatric bipolar disorder (PBD) has emerged as a field of research in which neuropsychological studies are continuously providing new empirical findings. Despite this, a comprehensive framework for neurocognitive impairments is still lacking, and most of the evidence remains unconnected. We addressed this question through a systematic review of neuropsychological research, with the aim of elucidating the main issues concerning this topic.

METHOD

A comprehensive search of databases (PubMed, PsycINFO) was performed. Published manuscripts between 1990 and January 2014 were identified. Overall, 124 studies fulfilled inclusion criteria. Methodological differences between studies required a descriptive review of findings.

RESULTS

Evidence indicates that verbal/visual-spatial memory, processing speed, working memory, and social cognition are neurocognitive domains impaired in PBD youth. Furthermore, these deficits are greater among those who suffer acute affective symptoms, PBD type I, and/or attention deficit hyperactivity disorder (ADHD) comorbidity. In addition, several neurocognitive deficits imply certain changes in prefrontal cortex activity and are somewhat associated with psychosocial and academic disabilities. Strikingly, these deficits are consistently similar to those encountered in ADHD as well as severe mood dysregulation (SMD). Besides, some neurocognitive impairments appear before the onset of the illness and tend to maintain stable across adolescence. Finally, any therapy has not yet demonstrated to be effective on diminishing these neurocognitive impairments.

LIMITATIONS

More prolonged follow-up studies aimed at delineating the course of treatment and the response to it are warranted.

CONCLUSIONS

Despite noteworthy research on the neurocognitive profile of PBD, our knowledge is still lagging behind evidence from adult counterparts.

Neuropsychological screening as a standard of care during discharge from psychiatric hospitalization: the preliminary psychometrics of the CNS Screen

Cost-prohibitive factors currently prevent a warranted integration of neuropsychological screenings into routine psychiatric evaluations, as a standard of care. To overcome this challenge, the current study examined the psychometric properties of a new computerized measure-the CNS Screen. One hundred and twenty six psychiatric inpatients completed the CNS Screen, the Montreal Cognitive Assessment (MoCA), and the Quick Inventory of Depressive Symptomatology-Self Rated (QIDS-SR₁₆) on the day of hospital discharge. Statistical analysis established convergent validity with a moderate correlation between the self-administered CNS Screen and the clinician-administered MoCA (r=0.64). Discriminant validity was implicated by a non-significant correlation with the QIDS-SR₁₆. Concurrent validity was supported by a moderate, negative correlation with patients' age (r=-0.62). In addition, consistent with previous findings, patients with psychotic disorders exhibited significantly poorer performance on the CNS Screen than patients with a mood disorder. Similarly, patients with a formal disability status scored significantly lower than other patients. The CNS Screen was well tolerated by all patients. With further development, this type of measure may provide a cost-effective approach to expanding neuropsychological screenings on inpatient psychiatric units.

Assessing the roles of stimulants/stimulant-like drugs and dopamine-agonists in the treatment of bipolar depression

Bipolar depression is considered the most difficult-to-treat phase of bipolar disorder, in relation to its pervasiveness and efficacy and/or tolerability limitations of available treatments. Indeed, most mood stabilizers and atypical antipsychotics are not as effective in ameliorating depressive compared with manic symptoms, and entail substantial tolerability limitations. However, the use of antidepressants is highly controversial, as their efficacy appears less robust in bipolar compared with unipolar depression. In addition, antidepressants, in spite of generally having adequate somatic tolerability, in BD may be associated with a higher risk of manic/hypomanic switch, suicidality and rapid cycling. Among alternative pharmacological strategies, compounds with stimulant and pro-dopaminergic effects, such as methylphenidate, modafinil, armodafinil and pramipexole, have showed potential antidepressant activity, even though their use in clinical practice has been limited by the paucity of controlled evidence. This article seeks to review available evidence about the use of the aforementioned compounds in the treatment of bipolar depression. Findings from reviewed studies suggested that pro-dopaminergic compounds, such as pramipexole and stimulants/stimulant-like agents, deserve consideration as adjunctive therapies in bipolar depressed patients, at least in some subgroups of patients. Nevertheless, caution regarding their use is recommended as further clinical trials with larger samples and longer follow-up periods are necessary to clarify the roles of these medications in bipolar depression.

Rodent models for mania: practical approaches

The scarcity of good animal models for bipolar disorder (BPD) and especially for mania is repeatedly mentioned as one of the rate-limiting factors in the process of gaining a better understanding into its pathophysiology and of developing better treatments. Standard models of BPD have some value but usually represent only one facet of the disease and have partial validity. A number of new approaches for modeling BPD and specifically mania have been suggested in the last few years and can be combined to improve models. These approaches include targeted mutation models representing reverse translation, the identification of advantageous strains for components of the disorder, a search for the most homologous species to address specific human pathology, and the exploration of individual differences of response including the separation between susceptible and resilient animals. Additionally, recent efforts have identified and developed new tests to distinguish between "normal" and "BPD-like" animals including the different utilization of known tests and novel tests such as the female-urine-sniffing test and behavior pattern monitor analysis. Additional tests relating to further domains of BPD are still needed. An ideal model for BPD that will encompass the entire disease and be useful for every demand will probably not become available until we have a full understanding of the pathophysiology of the disorder. However, the current advances in modeling should lead to better comprehension of the disorder and therefore to the gradual development of increasingly improved models.

Autonomic nervous system arousal and cognitive functioning in bipolar disorder

OBJECTIVE

Previous theories about the etiology of cognitive dysfunction in bipolar disorder (BD) emphasized trait factors such as neurological impairment. State factors, other than mood symptoms, that may exacerbate functional deficits have not yet been considered. The purpose of this study was to examine autonomic nervous system (ANS) arousal following cognitive challenge. The study compared patients with BD and healthy controls (HC) in physiological measures and neuropsychological test scores.

METHODS

Thirty euthymic patients with BD and 22 HC completed the study. Participants completed mood [Beck Depression Inventory-II (BDI-II) and Young Mania Rating Scale (YMRS)], anxiety (State-Trait Anxiety Inventory), and substance abuse (Drug Abuse Screening Test-20 item and Alcohol Use Disorders Identification Test) measures. They were connected to an electrogram, a sensitive thermometer for measuring finger temperature, and electrodes that measure galvanic skin response. After a five-min baseline measurement in a restful state, participants completed a computerized neuropsychological battery (CNS Vital Signs).

RESULTS

The group with BD reported significantly more mood symptoms (BDI-II, t = 3.71, p < 0.001; YMRS, t = 6.73, p < 0.001) and scored higher on a measure of trait-anxiety (State-Trait Anxiety Inventory, t = 2.91, p < 0.001) than HC. A multivariate analysis of variance revealed higher arousal on all physiological measures in the BD group relative to HC at baseline [F(3,48) = 13.1, p < 0.001] and during cognitive testing [F(3,48) = 11.3, p < 0.001]. The increase in physiological arousal from a restful state to the time of testing was higher for the BD group [F(3,37) = 8.06, p < 0.001]. With respect to cognitive data, HC scored higher than patients with BD across the measures of memory (F = 8.5, p < 0.001), sustained (F = 9.5, p < 0.001) and complex (F = 2.7, p < 0.04) attention, processing speed (F = 10.0, p < 0.001), reaction time (F = 7.8, p < 0.001), cognitive flexibility (F = 19.7, p < 0.001), working memory (F = 10.8, p < 0.001), and social acuity (F = 5.7, p < 0.01), with partial eta-squared from 0.18 to 0.62. Correlational analysis revealed significant associations between various cognitive test scores and changes in physiological arousal from baseline to testing (-0.59 ≤ r ≤ 0.22).

CONCLUSIONS

Relative to HC, patients with BD experience larger changes in ANS arousal between a restful baseline and cognitive testing, and achieve lower cognitive test scores. Further research is needed to determine whether acute physiological symptoms of anxiety directly compromise cognitive functioning in BD.

Toxoplasma gondii and cognitive deficits in schizophrenia: an animal model perspective

Cognitive deficits are a core feature of schizophrenia. Epidemiological evidence indicates that microbial pathogens may contribute to cognitive impairment in patients with schizophrenia. Exposure to Toxoplasma gondii (T. gondii) has been associated with cognitive deficits in humans. However, the mechanisms whereby the parasite impacts cognition remain poorly understood. Animal models of T. gondii infection may aid in elucidating the underpinnings of cognitive dysfunction. Here, we (1) overview the literature on the association of T. gondii infection and cognitive impairment, (2) critically analyze current rodent models of cognitive deficits resulting from T. gondii infection, and (3) explore possible mechanisms whereby the parasite may affect cognitive function.

The "selfish brain" hypothesis for metabolic abnormalities in bipolar disorder and schizophrenia

Metabolic abnormalities are frequent in patients with schizophrenia and bipolar disorder (BD), leading to a high prevalence of diabetes and metabolic syndrome in this population. Moreover, mortality rates among patients are higher than in the general population, especially due to cardiovascular diseases. Several neurobiological systems involved in energy metabolism have been shown to be altered in both illnesses; however, the cause of metabolic abnormalities and how they relate to schizophrenia and BD pathophysiology are still largely unknown. The "selfish brain" theory is a recent paradigm postulating that, in order to maintain its own energy supply stable, the brain modulates energy metabolism in the periphery by regulation of both allocation and intake of nutrients. We hypothesize that the metabolic alterations observed in these disorders are a result of an inefficient regulation of the brain energy supply and its compensatory mechanisms. The selfish brain theory can also expand our understanding of stress adaptation and neuroprogression in schizophrenia and BD, and, overall, can have important clinical implications for both illnesses.