A genome-wide association study of suicide severity scores in bipolar disorder

BackgroundSuicide claims one million lives worldwide annually, making it a serious public health concern. The risk for suicidal behaviour can be partly explained by genetic factors, as suggested by twin and family studies (reviewed in (Zai et al. 2012)). Recently, genome-wide association studies (GWASs) of suicide attempt on large samples of bipolar disorder (BD) patients from multiple sites have identified a number of novel candidate genes. GWASs of suicide behaviour severity, from suicidal ideation to serious suicide attempt, have not been reported for BD.MethodsWe conducted a GWAS of suicide behaviour severity in three independent BD samples:212 small nuclear families with BD probands from Toronto, Canada, 428 BD cases from Toronto, and 483 BD cases from the UK. We carried out imputation with 1000 Genome Project data as reference using IMPUTE2. Quality control and data analysis was conducted using PLINK and R. We conducted the quantitative analyses of suicide behaviour severity in the three samples separately, and derived an overall significance by a meta-analysis using the METAL software.ResultsWe did not find genome-wide significant association of any tested markers in any of the BD samples, but we found a number of suggestive associations, including regions on chromosomes 8 and 10 (p < 1e-5).ConclusionsOur GWAS findings suggest that likely many gene variants of small effects contribute collectively to the risk for suicidal behaviour severity in BD. Larger independent replications are required to strengthen the findings from the GWAS presented here.     

Prader–Willi syndrome: From genetics to behaviour,with special focus on appetite treatments

Prader–Willi syndrome (PWS) is a neurodevelopmental disorder resulting from a deletion in the expression of the paternally derived alleles in the region of 15q11–q13. PWS has a prevalence rate of 1:10,000–1:30,000 and is characterized by marked endocrine abnormalities including growth hormone deficiency and raised ghrelin levels.The hyperphagic phenotype in PWS is established over a number of phases and is exacerbated by impaired satiety, low energy expenditure and intellectual difficulties including obsessive–compulsive disorder and/or autistic behaviours. Clinical management in PWS typically includes familial/carer restriction and close supervision of food intake. If the supervision of food is left unmanaged, morbid obesity eventuates, central to the risk of cardiorespiratory disorder. None of the current appetite management/intervention strategies for PWS include pharmacological treatment, though recent research shows some promise.We review the established aberrant genetics and the endocrine and neuronal attributes which may determine disturbed regulatory processes in PWS. Focusing on clinical trials for appetite behaviours in PWS, we define the effectiveness of pharmacological treatments with a view to initiating and focusing research towards possible targets for modulating appetite in PWS.     

Applications of meta-analytic structural equation modelling in health psychology: examples,issues, and recommendations

ABSTRACT

Statistical methods play an important role in behavioural, medical, and social sciences. Two recent statistical advances are structural equation modelling (SEM) and meta-analysis. SEM is used to test hypothesised models based on substantive theories, which can be path, confirmatory factor analytic, or full structural equation models. Meta-analysis is used to synthesise research findings in a particular topic. This article demonstrates another recent statistical advance – meta-analytic structural equation modelling (MASEM) – that combines meta-analysis and SEM to synthesise research findings for the purpose of testing hypothesised models. Using the theory of planned behaviour as an example, we show how MASEM can be used to address important research questions that cannot be answered by univariate meta-analyses on Pearson correlations. Specifically, MASEM allows researchers to: (1) test whether the proposed models are consistent with the data; (2) estimate partial effects after controlling for other variables; (3) estimate functions of parameter estimates such as indirect effects; and (4) include latent variables in the models. We illustrate the procedures with an example on the theory of planned behaviour. Practical issues in MASEM and suggested solutions are discussed.     

Suicidal behaviour and memory: A systematic review and meta-analysis

Objectives. Suicidal behaviour results from a complex interplay between stressful events and vulnerability factors, including cognitive deficits. It is not yet clear if memory impairment is part of this specific vulnerability. Therefore, the objective of this study was to examine the association between memory deficits and vulnerability to suicidal acts. Methods. A literature review was performed using Medline, Embase, and PsycInfo databases. Twenty-four studies (including 2,595 participants) met the selection criteria. Four different types of memory (i.e., working memory, short- and long-term memory, and autobiographical memory) were assessed in at least three different studies. Results. Autobiographical memory was significantly less specific and more general in patients with a history of suicide attempt relative to those without such a history (Hedges’ g = 0.8 and 0.9, respectively). Long-term memory and working memory were both more impaired in suicide attempters than in patient and healthy controls. Only short-term memory did not differentiate suicide attempters from patient controls. Conclusions. Memory may play a significant role in the risk of suicidal acts, perhaps by preventing these individuals from using past experiences to solve current problems and to envision the future, and by altering inhibitory processes. More studies are necessary to better clarify these relationships.     

Body weight status misperception and its association with weight control behaviours,depressive mood and psychological distress in nulliparous normal-weight young women

Background: Understanding body weight status dissatisfaction may be important for understanding weight control behaviours and mental health.

Aims: To investigate the relationships between body weight status misperceptions in nulliparous normal-weight young women and weight control-related behaviours and mental health.

Subjects and methods: Body weight perceptions, weight control methods, depressive mood and psychological distress were measured in 717 nulliparous normal-weight women, aged 18–40 years, who participated in the 2007–2009 Korean National Health and Nutrition Examination Surveys (KNHANES-IV).

Results: Among 717 participants, 24 subjects (4.1?±?1.0%) misperceived themselves to be underweight and 295 subjects (39.2?±?2.2%) misperceived themselves to be overweight. Those with overweight misperceptions were more likely to fail to maintain their targeted body weights, despite weight control efforts (p?p?Conclusions: Body weight status misperception may be important for understanding weight control-related behaviours and psychiatric illness among nulliparous normal-weight young women.