Empirical evidence for discrete neurocognitive subgroups in bipolar disorder: clinical implications.

BACKGROUND: Recent data suggest trait-like neurocognitive impairments in bipolar disorder (BPD), with deficits about 1 s.d. below average, less severe than deficits noted in schizophrenia. The frequency of significant impairment in BPD is approximately 60%, with 40% of patients characterized as cognitively spared. This contrasts with a more homogeneous presentation in schizophrenia. It is not understood why some BPD patients develop deficits while others do not. METHOD: A total of 136 patients with BPD completed the MATRICS Consensus Cognitive Battery and data were entered into hierarchical cluster analyses to: (1) determine the optimal number of clusters (subgroups) that fit the sample; and (2) assign subjects to a specific cluster based on individual profiles. We then compared subgroups on several clinical factors and real-world community functioning. RESULTS: Three distinct neurocognitive subgroups were found: (1) an intact group with performance comparable with healthy controls on all domains but with superior social cognition; (2) a selective impairment group with moderate deficits on processing speed, attention, verbal learning and social cognition and normal functioning in other domains; and (3) a global impairment group with severe deficits across all cognitive domains comparable with deficits in schizophrenia. CONCLUSIONS: These results suggest the presence of multiple cognitive subgroups in BPD with unique profiles and begin to address the relationships between these subgroups, several clinical factors and functional outcome. Next steps will include using these data to help guide future efforts to target these disabling symptoms with treatment.

Initial evidence for sex-specific effects of early emotional abuse on affective processing in bipolar disorder.

PURPOSE: This study investigates the effect of sex and childhood trauma on affective processing in bipolar disorder (BPD) patients. METHODS: In a sample of fifty-six BPD patients, we administered the Childhood Trauma Questionnaire (CTQ), and the Iowa Gambling Task (IGT) and the Affective Go/No-Go (AGNG) to measure affective processing. Analysis of Variance (ANOVA) was used to evaluate the effect of sex and childhood trauma on IGT; Repeated-Measures ANOVAs to measure accuracy and bias measures across conditions on the AGNG. RESULTS: In the context of childhood abuse, females evidenced a more conservative cognitive style than males by selecting fewer cards from the disadvantageous decks [F(1, 49)=14.218; P<0.001] and showed an improvement throughout the task, as noted in a normal learning curve [F(1.49)=4.385; P=0.041)]. For the AGNG, an interaction specific to the negative valence stimuli on response bias measures was found. Abused females scored higher (mean=8.38; SD=6.39) than abused males (mean=0.69; SD=1.19) [F(1.46)=6.348; P=0.015]. CONCLUSION: Severity of childhood trauma was significantly different between sexes. In the context of a history of emotional abuse, male bipolar patients tended toward a more risk-taking behavior compared to female. Further investigations are needed to elucidate potential pathophysiological mechanisms underlying this interaction.