Substance related disorders are associated with impaired valuation of delayed gratification and feedback processing: A multilevel meta-analysis and meta-regression

Across numerous studies, individuals with substance use disorders (SUDs) differed from non-using controls regarding valuation of delayed gratification and feedback processing. However, it remains unclear whether the magnitude of the effect sizes is different across these two cognitive processes and how specific SUDs as well as demographic and clinical moderators influence these effects. In this study we thus performed multilevel linear mixed-effects meta-analyses and meta-regressions to examine the effects of SUDs on the Delay Discounting Task (DD) and on the Iowa Gambling Task (IGT). We found a moderate to large effect for SUD on both, the IGT and DD. While the effect on the DD was generalized to all substance classes, a smaller effect for cannabis-related disorder when compared to other SUDs was found with regard to the IGT. Early onset of substance use and psychiatric comorbidities were associated with stronger effects on the DD. Our findings suggest that feedback processing is more vulnerable to specific substance effects, while valuation of delayed gratification depends more on developmental and clinical factors.

Dual influences of early life stress induced by limited bedding on walking adaptability and Bdnf/TrkB and Drd1/Drd2 gene expression in different mouse brain regions

Introduction Evidence suggests early life stress impairs development, quality of life and increases vulnerability to disease. One important aspect of the stress experience is its impact on cognitive-motor performance, which includes the ability to adapt walking according to the environmental conditions. This study aimed to investigate how early-life stress affects walking adaptability of mice, while investigating BDNF/TrkB and Drd1/Drd2 expression in different brain regions. Methods Briefly, we exposed male C56BL/6 to the limited bedding protocol (LB) from post-natal day (PND) 2 to PND9 and then tested animals in the ladder walking task at PND60. RT-qPCR was used to investigate gene expression in the mPFC, hippocampus, motor cortex and cerebellum 2 h after the task Results LB induced a wide range of variability and therefore two distinct subgroups of animals within the LB group were established: a) superior performance (LB-SP); and b) inferior performance (LB-IP), compared to controls. Additionally, Drd1 gene expression was increased in the mPFC of LB-IP animals and in the cerebellum of LB-SP animals, while Drd2 expression was reduced in the hippocampus of the LB-IP group. BDNF exon IV gene expression in the mPFC and motor cortex was increased in both the LB-IP and LB-SP subgroups. TrkB gene expression in the hippocampus was reduced in the LB-IP group. A strong negative correlation was found between walking adaptability performance and BDNF exon IV gene expression in the motor cortex. Conversely, a positive correlation was found between walking adaptability performance and TrkB expression in the mPFC and a negative correlation in the hippocampus. Both Drd1 and Drd2 gene expression were negatively correlated with the ability to adapt walking. Conclusions Overall, our findings suggest exposure to early life stress leads to distinct walking adaptability phenotypes, which may be related to Drd1, Drd2, Bdnf exon IV and TrkB gene expression in brain regions that influence walking adaptability.

Inflammation, neurotrophism and oxidative stress and childhood psychopathology in a large community sample

OBJECTIVE

To investigate the association between peripheral biomarkers and child psychopathology in a large community sample.

METHOD

A total of 625 aged 6- to 13-year old subjects were recruited from a community school-based study. Psychopathology was assessed using the Child Behaviour Checklist (CBCL). Psychiatric diagnosis was evaluated using the Development and Well-Being Assessment. The following biomarkers were examined in peripheral blood: brain-derived neurotrophic factor, cytokines (IL-2, IL-4, IL-6, IL-10, IL-17, IFN-g, and TNF-α), chemokines (eotaxin/CCL11, IP-10, MCP-1), cytokine receptors (sTNFR1 and sTNFR2), and the oxidative stress marker TBARS.

RESULTS

We found significant associations between sTNFR2, eotaxin/CCL11 and CBCL total score, as well as with specific dimensions of psychopathology. There were different patterns of association between these biomarkers and psychological and behavioural symptoms in children with and without a mental disorder. TBARS, IL-6 and MCP-1 were more specific to some clusters of symptoms in children with a psychiatric diagnosis.

CONCLUSION

Our data support the potential use of biomarkers, especially those involved in immune-inflammatory pathways, in investigating neurodevelopmental psychopathology. Their association with different dimensions of symptoms might be of useful when analyzing illness severity and clusters of symptoms within specific disorders.

Childhood maltreatment and inflammatory markers: a systematic review

OBJECTIVE

Childhood maltreatment (CM) has been associated with several diseases in adult life, including diabetes, obesity and mental disorders. Inflammatory conditions have been postulated as possible mediators of this relationship. The aim was to conduct a systematic review regarding the association between CM and inflammatory markers in adulthood.

METHOD

A literature search of the PubMed, ISI, EMBASE and PsychINFO databases was conducted. The key terms used were as follows: 'Child Maltreatment', 'Childhood Trauma', 'Early Life Stress', 'Psychological Stress', 'Emotional Stress', 'Child Abuse' and 'Child Neglect'. They were cross-referenced separately with the terms: 'C-reactive Protein (CRP)', 'Tumor Necrosis Factor', 'Cytokine', 'Interleukin', 'Inflammatory' and 'Inflammation'.

RESULTS

Twenty articles remained in the review after exclusion criteria were applied. Studies showed that a history of CM was associated with increased levels of CRP, fibrinogen and proinflammatory cytokines. Increased levels of circulating CRP in individuals with a history of CM were the most robust finding among the studies. Data about anti-inflammatory mediators are still few and inconsistent.

CONCLUSION

Childhood maltreatment is associated with a chronic inflammatory state independent of clinical comorbidities. However, studies are heterogeneous regarding CM assessment and definition. Important methodological improvements are needed to better understand the potential impact of CM on inflammatory response.

Executive functions rehabilitation for schizophrenia: a critical systematic review

BACKGROUND

Consistent evidences suggest that poor functional outcomes in schizophrenia are associated with deficits in executive functions (EF). As result cognitive training, remediation and/or rehabilitation (CR) programs have been developed and many theories, methods and approaches have emerged in support of them. This article presents a systematic review of randomized controlled trials (RCT), including EF rehabilitation interventions, with a focus on methodological issues and evidences of EF improvements.

METHOD

Electronic databases (Medline, Web of Science, PsycINFO and Embase) were searched for articles on schizophrenia, EF and cognitive rehabilitation terms. The methodological quality of each article was measured by 5-point JADAD scale.

RESULTS

A total of 184 articles were initially identified, but after exclusion criteria, 30 RCT remained in this review. A proportion of 23% of studies scored higher than 4 points in JADAD scale, 40% scored 3 points, 33% scored 2 points and one study scored only 1 point. The average length of interventions was approximately 80 h distributed around 3.42 h/week.

CONCLUSION

The reviewed articles corroborate the literature pointing that CR could be a promising therapeutic option for cognitive deficits in schizophrenia. In general, CR could improve cognitive domains and social adjustment either using computerized or paper-and-pencil programs. Additionally, CR combined with cognitive behavioral therapy and/or group sessions is particularly effective. In this paper, we also speculated and discussed optimal doses of treatment and the differences regarding modalities and approaches.

Childhood maltreatment and clinical outcomes of bipolar disorder

OBJECTIVE

Adverse life events, especially early trauma, play a major role in the course and expression of bipolar disorder (BD). The aim of this article is to present a systematic review about the impact of childhood trauma on the clinical course of BD.

METHOD

A computer-aided search was performed in Medline, ISI database, EMBASE, PsychInfo, Centre for Reviews and Dissemination, and Databases of Thomson Reuters at April 2011, supplemented by works identified from the reference lists of the first selected papers. Two investigators systematically and independently examined all articles, selecting those according inclusion and exclusion criteria.

RESULTS

Four hundred fifteen articles were identified, of which 19 remained in the review after exclusion criteria were applied. In general, childhood maltreatment predicted worsening clinical course of BD. After assessing the quality of the data and of the measurements, childhood maltreatment can be strongly associated to early onset of disorder, suicidality, and substance abuse disorder in patients with BD.

CONCLUSION

Data suggest that childhood abuse and neglect are risk factors associated with worsening clinical course of BD. The conclusions should be interpreted with caution because all the studies included are cross-sectional and the majority are showing inconsistencies regarding childhood trauma as independent variable and how it is assessed.