Bipolar subtypes and their clinical correlates in a sample of 391 bipolar individuals.

Differences between BD-I and BD-II patients with regard to specific illness characteristics are poorly understood. This study is mainly aimed to compare socio-demographic and clinical characteristics between BD-I and BD-II patients with the goal of clarifying possible predictors of clinical course. The sample of this cohort study is composed of 391 currently euthymic bipolar patients. Participants were all receiving only maintenance treatment; their psychopharmacological regimens and psychopathological conditions were stable at assessment. After univariate analyses, BD-II patients were more likely to be female, had more frequently a recent depressive episode and substance abuse/dependence relative to BD-I subjects. BD-II patients were also less likely to have a positive history of psychiatric conditions in family, psychotic symptoms at first episode, and first depressive illness episode. Moreover, BD-II were older at their illness onset and first treatment than BD-I patients. Furthermore, BD-I were more likely to have higher depressive, manic, anxiety, and symptoms severity than BD-II patients. After logistic regression analyses, being female (OR = 0.289), having psychiatric conditions in family (OR = 0.273), and higher severity of illness at CGI (OR = 0.604) were all significantly associated with BD-II. Additional studies are required to replicate these results, and facilitate the prediction of BD outcomes according to the specified profile.

Bipolar disorder type I and II show distinct relationships between cortical thickness and executive function.

OBJECTIVE: Frontal cortical abnormalities and executive function impairment co-occur in bipolar disorder. Recent studies have shown that bipolar subtypes differ in the degree of structural and functional impairments. The relationships between cognitive performance and cortical integrity have not been clarified and might differ across patients with bipolar disorder type I, II, and healthy subjects. METHOD: Using a vertex-wise whole-brain analysis, we investigated how cortical integrity, as measured by cortical thickness, correlates with executive performance in patients with bipolar disorder type I, II, and controls (N = 160). RESULTS: We found focal associations between executive function and cortical thickness in the medial prefrontal cortex in bipolar II patients and controls, but not in bipolar I disorder. In bipolar II patients, we observed additional correlations in lateral prefrontal and occipital regions. CONCLUSIONS: Our findings suggest that bipolar disorder patients show altered structure-function relationships, and importantly that those relationships may differ between bipolar subtypes. The findings are line with studies suggesting subtype-specific neurobiological and cognitive profiles. This study contributes to a better understanding of brain structure-function relationships in bipolar disorder and gives important insights into the neuropathophysiology of diagnostic subtypes.

Cognitive Performance in Euthymic Patients with Bipolar Disorder vs Healthy Controls: A Neuropsychological Investigation.

OBJECTIVES: Cognitive impairment may affect patients with Bipolar Disorder (BD) beyond the acute episodes, qualifying as a potential endophenotype. However, which cognitive domains are specifically affected in euthymic patients with BD and the potential influence of confounding factors (e.g., age and concomitant pharmacological treatment) are still a matter of debate. The present study was, therefore, conducted to assess cognitive performance across specific domains in euthymic bipolar patients, not older than 50 years (to avoid potential age-related bias) versus healthy controls (HCs). METHODS: A cognitive task battery, including the Wisconsin Card Test, Span Attention Test, Tower of London, Trail Making Test, Verbal Fluency Test, Matrices Scores and N-Back, was administered to 62 subjects (30 bipolar patients and 32 matched HCs) and differences between the groups analyzed. RESULTS: Bipolar patients performed significantly worse than HCs in the Span Forward task, in the expression of Verbal Fluency Test (Category) and in the N-Back task (all p<.05), with marginal differences between BD I and BD II patients. CONCLUSION: The present study pointed out significant differences in terms of cognitive performance between euthymic bipolar patients and HCs, supporting the notion that specific cognitive functions may remain impaired even after the resolution of the acute episodes in subjects suffering from BD. Future studies on larger samples are warranted to confirm the present results and further explore potential differences in cognitive impairment across specific bipolar subtypes.

Genetic variants of the BDNF and DRD3 genes in bipolar disorder comorbid with anxiety disorder.

BACKGROUND: The high comorbidity rate between bipolar disorder (BP) and anxiety disorder (AD) has been studied in depth. This comorbidity is not as high in Han Chinese in Taiwan. Therefore, we explored the genetic effects BP comorbid with AD. METHODS: We recruited 1316 participants: 286 with BP-I, 681 with BP-II, and 349 healthy Controls. Genotypes of the BDNF Val66Met and DRD3 Ser9Gly polymorphisms were determined using polymerase chain reactions plus restriction fragment length polymorphism analysis. RESULTS: The DRD3 Ser9Gly polymorphism was associated with BP-II comorbid with AD (BPII(+AD)), and the BDNF Val66Met polymorphism was associated with BP-I comorbid with AD (BPI(+AD)). An interaction between the Val/Val genotype of the BDNF Val66Met and Gly/Gly polymorphism of the DRD3 Ser9Gly was found in BPII(+AD), but not in BP-II not comorbid with AD (BPI(-AD)) compared with healthy Controls. LIMITATION: The low comorbidity rate of AD in both BP subtypes, especially BP-I, limit generalizing our findings. CONCLUSION: The involvement of the dopaminergic pathway in AD was confirmed, particularly with BP-II rather than BP-I. Because the Val/Val genotype of the BDNF Val66Met polymorphism, rather than the other two polymorphisms, has been associated with anxiety, it seems to affect BP-I comorbid with AD without the involvement of the DRD3 Seg9Gly polymorphism, but may modify the involvement of DRD3 Gly/Gly in BP-II comorbid with AD.

Behavioral Activation System (BAS) differences in bipolar I and II disorder.

BACKGROUND: A growing body of evidence supports the Behavioral Activation System (BAS) dyresgulation model of bipolar disorder, however its application to bipolar II disorder is limited. The current study examines its potential relevance to bipolar I and II disorders. We specifically sought to determine whether bipolar sub-types would differ in terms of BAS sensitivity, and examined for differential prospective relationships between BAS sensitivity and bipolar I and II symptom expression. METHOD: Participants were recruited from the Sydney-based Black Dog Institute. Diagnostic groups were derived on the basis of agreement between clinician and DSM-IV diagnoses from structured interviews. Baseline measures of BAS sensitivity, mood symptoms and anxiety were completed. Self-rated mood was assessed over a 6-month period. Clinician-rated mood status was re-assessed at follow-up to determine the predictive utility of BAS scores. RESULTS: The sample comprised 151 bipolar participants (69 bipolar I, 82 bipolar II). BAS-Drive and Reward Responsiveness scores were significantly higher in bipolar I disorder participants. BAS sub-scale scores were uniquely positively associated with mood variability in bipolar I and II disorder. BAS-Drive and Reward Responsiveness scores were positively associated with bipolar I hypo(mania), and with the former also positively associated with bipolar II depression. BAS scores did not predict bipolar I or II mood episode status at 6-month follow-up. LIMITATIONS: BAS sensitivity was self-reported; inability to establish independence of BAS scores from residual symptoms; lack of controlling for medication effects; inability to determine the influence of life events; length of follow-up period may have not been sufficient to evaluate the predictive utility of BAS sensitivity for mood episodes or detect course of illness differences across bipolar sub-types. CONCLUSIONS: Differences in BAS sensitivity and associations with mood variability were quantified in bipolar I and II disorder, suggesting the need for tailored treatments for these separate conditions. Further investigation of the role of the BAS in bipolar sub-types is warranted.