Cognitive heterogeneity in the offspring of patients with schizophrenia or bipolar disorder: a cluster analysis across family risk.

BACKGROUND: Neurocognitive impairment is considered to lie on a continuum of severity across schizophrenia (SZ) and bipolar disorder (BP), possibly reflecting a gradient of neurodevelopmental load. Cluster analyses have identified different levels of impairment across the two disorders, from none to widespread and severe. We for the first time used this approach to examine cognitive function pooling together children and adolescents at familial risk of SZ or BP. METHODS: 220 participants, 49 offspring of individuals with schizophrenia (SZO), 90 offspring of individuals with bipolar disorder (BPO) and 81 offspring of healthy control parents (HC), aged 6 to 17 years, underwent a comprehensive clinical and cognitive assessment. Cognitive measures were used to group SZO and BPO using K-means clustering. Cognitive performance within each of the clusters was compared to that of HC and clinical variables were compared between clusters. RESULTS: We identified three cognitive subgroups: a moderate impairment group, a mild impairment group, and a cognitively intact group. Both SZO and BPO were represented in each of the clusters, yet not evenly, with a larger proportion of the SZO in the moderately impaired cluster, but also a subgroup of BPO showing moderate cognitive dysfunction. LIMITATIONS: Participants have yet to reach the age of onset for the examined disorders. CONCLUSIONS: The findings point to a range of neurodevelopmental loadings across youth at familial risk of both SZ and BP. They have therefore important implications for the stratification of cognitive functioning and the possibility to tailor interventions to individual levels of impairment.

Comorbidity between bipolar disorder and borderline personality disorder: Prevalence, explanatory theories, and clinical impact.

BACKGROUND: The relationship between bipolar disorder (BD) and borderline personality disorder (BPD) has been controversial and widely debated. Specifically, the comorbidity between both disorders has yielded a plethora of research, but there are no comprehensive reviews on this issue. OBJECTIVE: To determine the empirical evidence regarding the comorbidity between BD and BPD based on prevalence data, explanatory theories for their co-occurrence, and clinical impact of one disorder in the other. METHOD: A comprehensive search of databases (PubMed and PsycINFO) was performed. Published manuscripts between January 1985 and August 2015 were identified. Overall, 70 studies fulfilled inclusion criteria. RESULTS: Over a fifth of subjects showed comorbidity between BPD and BD. Empirical evidence from common underlying factors was inconclusive, but BPD appears to be a risk factor for BD. Data also indicated that the negative impact of BPD in BD (e.g., suicidality, worse mood course) was greater than vice verse. CONCLUSIONS: Given the high prevalence of comorbidity between BD and BPD and the negative effects of BPD in subjects with BD, further studies are needed to clarify the factor associated with the comorbidity between these two disorders. This information is important to develop appropriate treatments for subjects with both disorders, improve their clinical course, and prevent the increased risk of suicidality commonly found in these subjects.