Shared impairment in associative learning in schizophrenia and bipolar disorder

Background

Schizophrenia (SCZ) and bipolar disorder (BD) share some cognitive commonalities. However, the role of associative learning, which is a cornerstone of human cognition mainly relying on hippocampus, has been under-investigated. We assessed behavioral performance during associative learning in a group of SCZ, BD and healthy controls (HC).

Methods

Nineteen patients with SCZ (36 ± 8.1 years; 13 males, 6 females; all Caucasians), 14 patients with BD (41 ± 9.6 years; 5 males, 9 females; all Caucasians) and 45 HC (27.7 ± 6.9 years; 18 males, 27 females; all Caucasians) were studied. Learning was assessed using an established object-location paired-associative learning paradigm. Subjects learned associations between nine equi-familiar common objects and locations in a nine-location grid. Performance data were analyzed in a repeated measures analysis of variance with time (repeated) and group as factors.

Results

Learning curves (performance = 1−e^−k?time) fitted to average performance data in the three groups revealed lower learning rates in SCZ and BD (k = 0.17 and k = 0.34) than HC (k = 0.78). Significant effects of group (F = 11.05, p < 0.001) and time (F = 122.06, p < 0.001) on learning performance were observed.

Conclusions

Our study showed that associative learning is impaired in both SCZ and BD, being potentially not affected by medication. Future studies should investigate the neural substrates of learning deficits in SCZ and BD, particularly focusing on hippocampus function and glutamatergic transmission.     

A genetic schizophrenia-susceptibility region located between the ANKK1 and DRD2 genes

Background

The gene coding for the D2 dopamine receptor (DRD2) is considered to be one of the most pertinent candidate genes in schizophrenia. However, genetic studies have yielded conflicting results whereas the promising TaqIA variant/rs1800497 has been mapped in a novel gene, ANKK1.

Methods

We investigated eleven single nucleotide polymorphisms (SNPs) spanning the DRD2 and ANKK1 genes, using both a case–control association study comparing 144 independent patients to 142 matched healthy subjects, and a transmission disequilibrium test in 108 trios. This classical genetic study was coupled with a cladistic phylogeny-based association test of human variants, and with an interspecies evolution study of ANKK1.

Results

Case–control study, followed by a 108 trios family-based association analysis for replication, revealed an association between schizophrenia and the ANKK1 rs1800497 (p = 0.01, Odds Ratio = 1.5, 95% Confidence Interval = 1.1–2.2), and the intergenic rs2242592 (p = 2 · 10^− 4, OR = 1.8, 95%CI = 1.3–2.5). A significant SNP–SNP interaction was also found (p < 10^− 5, OR = 2.0, 95%CI = 1.6–2.5). The phylogeny-based association test also identified an association between both these polymorphisms and schizophrenia. Finally, interspecies comparison of the sequences from chimpanzee, orangutan, rhesus macaque and human species suggested specific involvement of ANKK1 in the human lineage.

Conclusions

Intergenic rs2242592 appears to be involved in the genetic vulnerability to schizophrenia, whereas the ANKK1 rs1800497 appears to have a modifying rather than causative effect. Finally, ANKK1 may be a specific human lineage-trait involved in a specific human disease, schizophrenia.     

The BDNF Val66Met polymorphism is an independent risk factor for high lethality in suicide attempts of depressed patients

Some authors have reported an association of BDNF Val66Met polymorphism with suicidal behavior and/or clinical aspects of suicidal attempts. We evaluated, here, the impact of BDNF Val66Met polymorphism on the clinical characteristics of suicide attempts. The study was conducted on a cohort of 120 consecutive patients who were admitted to the Emergency Hospital of Porto Alegre, Brazil, due to a suicide attempt. Variables of univariate analyses were included in a logistic regression model to test whether the risk factors had independent effect. In univariate analyses, sex, BDNF genotype, intent and method of suicide attempt were all risk factors for high lethality in suicide attempts. After logistic regression analysis, male sex (O.R. = 3.03; 95% C.I = 1.34–6.84; 0.008) and the presence of BDNF 66Met allele (O.R. = 2.62; 95% C.I = 1.04–6.57; 0.04) were significantly and independently associated with the high lethality in suicide attempts. The present study showed that BDNF 66Met allele is an independent predictor of high lethality in suicide attempts of depressed patients. This finding is important because it might allow earlier identification of patients at high risk for suicide, perhaps providing better tools for clinical care of these patients in the future.     

The meaning of burden of care in a faith-based community: the case of ultra-Orthodox Jews (UOJ)

Objectives: The context of caregiving in the ultra-Orthodox Jewish community is still an uncharted field. We sought to facilitate an in-depth understanding of caregivers in Israel through their views of their position as primary caregivers, their coping mechanisms with the challenges of caregiving burden, and their unfulfilled needs.

Method: Data were drawn from interviews with 28 participants, serving as primary caregivers for at least a year.

Results: Three major themes emerged from the data analysis: (1) burden of care as a universal experience, (2) the faith-based spiritual meaning of caring for parents, and (3) modest needs and expectations from the formal services – a total reliance on the familial-community service system, while there is some indication of unfulfilled needs that should be addressed by the formal service system.

Conclusion: Intervening parties should be aware of the ‘cultural color,’ and not ignore the unique difficulties this population faces. Policy-makers should acknowledge the patterns of non-formal services used in this community.     

脑卒中老人主要照顾者照顾负担现状及相关因素研究

目的了解住院老年脑卒中患者主要照顾者的照顾负担并分析其影响因素。方法应用照顾者负担量表(caregiver burden inventory,CBI)、社会支持评定量表(social support rating scale,SSRS)、照顾者积极感受量表(positive aspects of caregiver,PAC),对211例住院老年脑卒中患者及其主要照顾者进行问卷调查。结果住院脑卒中患者子女照顾者的照顾负担得分总分(57.37±10.15)分,对应条目均分为(2.39±0.42)分。逐步多元回归分析显示,住院老年脑卒中患者BI指数、有无抑郁,照顾者年龄、照顾年限、社会支持水平、照顾者积极感受为照顾负担的影响因素。结论脑卒中照顾者的照顾负担亟待重视,其影响因素涉及多个方面。医护人员应针对相关因素,帮助减轻照顾者和老年脑卒中患者双方负担。     

Robots de téléprésence et intersubjectivation

Objectives

The aim of this paper was to analyze the experiences of students to whom a telepresence robot was made available in periods during which they were prevented from attending university courses.

Autobiographical memory in mild cognitive impairment and Alzheimer's disease: A comparison between the Levine and Kopelman interview methodologies

Previous studies have produced inconsistent results concerning the two components of autobiographical memory—personal semantic memory and episodic memory. Results in subjects with mild cognitive impairment (MCI) and dementia of Alzheimer's type (DAT) have varied concerning the existence of a temporal gradient in retrograde amnesia. These results have important theoretical implications regarding multiple trace theory versus standard consolidation models of long‐term memory (LTM). We investigated whether this variability arises from differences in the methods used in assessing autobiographical memory. We examined patterns of memory impairment in 20 healthy elderly controls, 20 MCI subjects, and 10 DAT subjects using the Autobiographical Memory Interview (AMI) of Kopelman and the Autobiographical Interview (AI) of Levine. Both the AMI and AI were modified to allow for the test scores to be derived from a single interview without fatiguing the subjects. On the AMI, DAT subjects were significantly impaired on both components of autobiographical memory—episodic memory and personal semantics—with episodic memory showing a significant though gentle temporal gradient sparing childhood memories. Using the AI test, subjects with DAT showed impaired recall of episodic details (but not personal semantics), again with a gentle temporal gradient. Differences between the two interview methods (fewer epochs in the AMI; fewer memories per epoch in the AI) were found to have a significant impact on the pattern of findings; fewer epochs in the AMI brought out the temporal gradient, and fewer memories per epoch (in the AI) diminished it. These data show the importance of technical details of the different tests in favouring one versus another LTM theory. The data are not purely compatible with either theory. © 2012 Wiley Periodicals, Inc.     

Cannabis induces different cognitive changes in schizophrenic patients and in healthy controls

It is known that 60 to 80% of schizophrenic patients show deficits in cognition. There may be an increase in these deficits as a result of additional regular use of cannabis. The aim of the study was to evaluate the effect of chronic cannabis consumption on the cognitive functions of schizophrenic patients and healthy control subjects after a minimum abstinence time of 28 days. The study sample consisted of 39 schizophrenics (19 cannabis-abusers and 20 non-abusers) and 39 healthy controls (18 cannabis-abusers, 21 non-abusers). In a 2x2-factorial design (Diagnostic Groups [healthy controls, schizophrenic patients]xCannabis abuse [without, with]) with diagnostic group and cannabis consumption considered between-subject factors) we tested the hypothesis that dually diagnosed patients (i.e. suffering both from schizophrenia and cannabis abuse) perform worse in neuropsychological tests than schizophrenic patients without cannabis abuse. On the whole, schizophrenic patients performed worse than healthy control subjects. Surprisingly, rather than deteriorating neuropsychological performance, regular cannabis abuse prior to the first psychotic episode improved cognition in some tests. This was even more pronounced when regular consumption started before the age of 17. On the other hand, cannabis use deteriorated test performance in healthy controls, especially in cases when regular consumption started before the age of 17. To sum up, regular cannabis abuse has a different effect on cognitive function in schizophrenic patients and healthy controls.     

Identification of Youth Psychosocial Problems During Pediatric Primary Care Visits

This investigation applied the Gateway Provider Model (GPM) of child mental health services to investigate whether characteristics of the child, family, visit, and provider were related to the identification of youth psychosocial problems during primary care visits. Data were gathered during 774 visits to 54 primary care providers (PCPs) at 13 clinics. Similar to previous investigations in primary care settings, 42% of youth demonstrated at least a sub-threshold clinical mental health problem. Most PCPs reported high job satisfaction and control, but reported varying access to mental health specialists. PCPs generally had positive attitudes and beliefs about treating psychosocial problems but many reported that doing so was burdensome. Identification was more likely when the visit was for a mental health problem, when issues related to psychosocial problems were discussed during the visit, when the youth demonstrated mental health symptoms, impairment, or burden to the family, and when the youth was older, uninsured, or received Medicaid. Identification was less likely when the PCP reported greater burden associated with treating psychosocial problems and when the PCP reported greater accessibility to mental health specialists. These results suggest that identification is associated with the interaction of multilevel factors and that the GPM is a useful model to investigate points of intervention for improving the identification of children’s mental health problems in primary care settings. Presented in part at the University of South Florida 18th Annual Research Conference: A System of Care for Children’s Mental Health, Tampa, FL, February 2006.