Daniel Stahl

A systematic review and meta-analysis of set-shifting ability in eating disorders

BACKGROUND The aim was to critically appraise and synthesize the literature relating to set-shifting ability in eating disorders. PsycINFO, Medline, and Web of Science databases were searched to December 2005. Hand searching of eating-disorder journals and relevant reference sections was also undertaken. METHOD The 15 selected studies contained both eating disorder and healthy control groups, and employed at least one of the following six neuropsychological measures of set-shifting ability; Trail Making Test (TMT), Wisconsin Card Sort Test (WCST), Brixton task, Haptic Illusion, CatBat task, or the set-shifting subset of the Cambridge Neuropsychological Test Automated Battery (CANTAB). The outcome variable was performance on the set-shifting aspect of the task. Pooled standardized mean differences (effect sizes) were calculated. RESULTS TMT, WCST, CatBat and Haptic tasks had sufficient sample sizes for meta-analysis. These four tasks yielded acceptable pooled standardized effect sizes (0.36; TMT -1.05; Haptic) with moderate variation within studies (as measured by confidence intervals). The Brixton task showed a small pooled mean difference, and displayed more variation between sample results. The effect size for CANTAB set shifting was 0.17. CONCLUSION Problems in set shifting as measured by a variety of neuropsychological tasks are present in people with eating disorders.

Daily use, especially of high-potency cannabis, drives the earlier onset of psychosis in cannabis users.

UNLABELLED Cannabis use is associated with an earlier age of onset of psychosis (AOP). However, the reasons for this remain debated. METHODS We applied a Cox proportional hazards model to 410 first-episode psychosis patients to investigate the association between gender, patterns of cannabis use, and AOP. RESULTS Patients with a history of cannabis use presented with their first episode of psychosis at a younger age (mean years = 28.2, SD = 8.0; median years = 27.1) than those who never used cannabis (mean years = 31.4, SD = 9.9; median years = 30.0; hazard ratio [HR] = 1.42; 95% CI: 1.16-1.74; P < .001). This association remained significant after controlling for gender (HR = 1.39; 95% CI: 1.11-1.68; P < .001). Those who had started cannabis at age 15 or younger had an earlier onset of psychosis (mean years = 27.0, SD = 6.2; median years = 26.9) than those who had started after 15 years (mean years = 29.1, SD = 8.5; median years = 27.8; HR = 1.40; 95% CI: 1.06-1.84; P = .050). Importantly, subjects who had been using high-potency cannabis (skunk-type) every day had the earliest onset (mean years = 25.2, SD = 6.3; median years = 24.6) compared to never users among all the groups tested (HR = 1.99; 95% CI: 1.50- 2.65; P < .0001); these daily users of high-potency cannabis had an onset an average of 6 years earlier than that of non-cannabis users. CONCLUSIONS Daily use, especially of high-potency cannabis, drives the earlier onset of psychosis in cannabis users.

Central coherence in eating disorders: a systematic review

BACKGROUND This review systematically appraised the research evidence for local versus global information processing to test the hypothesis that people with eating disorders (ED) had weak central coherence. METHOD Searches on Medline, EMBASE, PsycINFO and ISI Web of Science databases were conducted in November 2006 and subsequently updated in September 2007. Each search was conducted in two steps: (1) neuropsychological tasks measuring central coherence and (2) words related to cognitive functioning in eating disorders. Data were summarized in a meta-analysis if the number of studies for a given test was >5. RESULTS Data were extracted from 16 studies. Meta-analyses were conducted for four tasks obtaining moderate effect sizes. The majority of studies found global processing difficulties across the ED spectrum. The results are less clear regarding local processing. CONCLUSIONS People with ED have difficulties in global processing. It is less certain as to whether they have superior local processing. Currently, there is insufficient evidence to refute the weak central coherence hypothesis.

A Cohort Study of People With Diabetes and Their First Foot Ulcer The role of depression on mortality

OBJECTIVE—The aim was to evaluate over 18 months whether depression was associated with mortality in people with their first foot ulcer. RESEARCH DESIGN AND METHODS—A prospective cohort design was used. Adults with their first diabetic foot ulcer were recruited from foot clinics in southeast London, U.K. At baseline, the Schedules for Clinical Assessment in Neuropsychiatry 2.1 was used to define those who met DSM (Diagnostic and Statistical Manual of Mental Disorders)-IV criteria for minor and major depressive disorders. Potential covariates were age, sex, marital status, socioeconomic status, smoking, antidepressant use, A1C, macro- and microvascular complications, and University of Texas classification–based severity and size of ulcer. The main outcome was mortality 18 months later, and A1C was the secondary outcome. The proportion who had an amputation, had recurrence, and whose ulcer had healed was recorded. RESULTS—A total of 253 people with their first diabetic foot ulcer were recruited. The prevalence of minor and major depressive disorder was 8.1% (n = 21) and 24.1% (n = 61), respectively. There were 40 (15.8%) deaths, 36 (15.5%) amputations, and 99 (43.2%) recurrences. In the adjusted Cox regression analysis, minor and major depressive disorders were associated with an approximately threefold hazard risk for mortality compared with no depression (3.23 [95% CI 1.39–7.51] and 2.73 [1.38–5.40], respectively). There was no association between minor and major depression compared with no depression and A1C (P = 0.86 and P = 0.43, respectively). CONCLUSIONS—One-third of people with their first diabetic foot ulcer suffer from clinical depression, and this is associated with increased mortality.

Sampling children's spontaneous speech: how much is enough?

There has been relatively little discussion in the field of child language acquisition about how best to sample from childrens spontaneous speech, particularly with regard to quantitative issues. Here we provide quantitative information designed to help researchers make decisions about how best to sample childrens speech for particular research questions (and/or how confident to be in existing analyses). We report theoretical analyses in which the major parameters are: (1) the frequency with which a phenomenon occurs in the real world, and (2) the temporal density with which a researcher samples the childs speech. We look at the influence of these two parameters in using spontaneous speech samples to estimate such things as: (a) the percentage of the real phenomenon actually captured, (b) the probability of capturing at least one target in any given sample, (c) the confidence we can have in estimating the frequency of occurrence of a target from a given sample, and (d) the estimated age of emergence of a target structure. In addition, we also report two empirical analyses of relatively infrequent child language phenomena, in which we sample in different ways from a relatively dense corpus (two children aged 2;0 to 3;0) and compare the different results obtained. Implications of these results for various issues in the study of child language acquisition are discussed.

Stress reduction through consolation in chimpanzees

Consolation, i.e., postconflict affiliative interaction directed from a third party to the recipient of aggression, is assumed to have a stress-alleviating function. This function, however, has never been demonstrated. This study shows that consolation in chimpanzees reduces behavioral measures of stress in recipients of aggression. Furthermore, consolation was more likely to occur in the absence of reconciliation, i.e., postconflict affiliative interaction between former opponents. Consolation therefore may act as an alternative to reconciliation when the latter does not occur. In the debate about empathy in great apes, evidence for the stress-alleviating function of consolation in chimpanzees provides support for the argument that consolation could be critical behavior. Consistent with the argument that relationship quality affects their empathic responses, we found that consolation was more likely between individuals with more valuable relationships. Chimpanzees may thus respond to distressed valuable partners by consoling them, thereby reducing their stress levels, especially in the absence of reconciliation.

A systematic review and meta-analysis of cognitive bias to food stimuli in people with disordered eating behaviour

AIM Maladaptive cognitions about food, weight and shape bias attention, memory and judgment and may be linked to disordered eating behaviour. This paper reviews information processing of food stimuli (words, pictures) in people with eating disorders (ED). METHOD PubMed, Ovid, ScienceDirect, PsychInfo, Web of Science, Cochrane Library and Google Scholar were searched to December 2009. 63 studies measured attention, memory and judgment bias towards food stimuli in women with ED. RESULTS Stroop tasks had sufficient sample size for a meta-analyses and effects ranged from small to medium. Other studies of attention bias had variable effects (e.g. the Dot-Probe task, distracter tasks and Startle Eyeblink Modulation). A meta-analysis of memory bias studies in ED and RE yielded insignificant effect. Effect sizes for judgment bias ranged from negligible to large. CONCLUSIONS People with ED have greater attentional bias to food stimuli than healthy controls (HC). Evidence for a memory and judgment bias in ED is limited.

Treatments of Negative Symptoms in Schizophrenia: Meta-Analysis of 168 Randomized Placebo-Controlled Trials

OBJECTIVES Existing treatments for schizophrenia can improve positive symptoms, but it is unclear if they have any impact on negative symptoms. This meta-analysis was conducted to assess the efficacy of available treatments for negative symptoms in schizophrenia. METHODS All randomized-controlled trials of interventions for negative symptoms in schizophrenia until December 2013 were retrieved; 168 unique and independent placebo-controlled trials were used. Negative symptom scores at baseline and follow-up, duration of illness, doses of medication, type of interventions, and sample demographics were extracted. Heterogeneity was addressed with the I (2) and Q statistic. Standardized mean difference in values of the Negative Symptom Rating Scale used in each study was calculated as the main outcome measure. RESULTS 6503 patients in the treatment arm and 5815 patients in the placebo arm were included. No evidence of publication biases found. Most treatments reduced negative symptoms at follow-up relative to placebo: second-generation antipsychotics: -0.579 (-0.755 to -0.404); antidepressants: -0.349 (-0.551 to -0.146); combinations of pharmacological agents: -0.518 (-0.757 to -0.279); glutamatergic medications: -0.289 (-0.478 to -0.1); psychological interventions: -0.396 (-0.563 to -0.229). No significant effect was found for first-generation antipsychotics: -0.531 (-1.104 to 0.041) and brain stimulation: -0.228 (-0.775 to 0.319). Effects of most treatments were not clinically meaningful as measured on Clinical Global Impression Severity Scale. CONCLUSIONS AND RELEVANCE Although some statistically significant effects on negative symptoms were evident, none reached the threshold for clinically significant improvement.

Cognitive Flexibility and Clinical Severity in Eating Disorders

Objectives The aim of this study was to explore cognitive flexibility in a large dataset of people with Eating Disorders and Healthy Controls (HC) and to see how patient characteristics (body mass index [BMI] and length of illness) are related to this thinking style. Methods A dataset was constructed from our previous studies using a conceptual shift test - the Brixton Spatial Anticipation Test. 601 participants were included, 215 patients with Anorexia Nervosa (AN) (96 inpatients; 119 outpatients), 69 patients with Bulimia Nervosa (BN), 29 Eating Disorder Not Otherwise Specified (EDNOS), 72 in long-term recovery from AN (Rec AN) and a comparison group of 216 HC. Results The AN and EDNOS groups had significantly more errors than the other groups on the Brixton Test. In comparison to the HC group, the effect size decrement was large for AN patients receiving inpatient treatment and moderate for AN outpatients. Conclusions These findings confirm that patients with AN have poor cognitive flexibility. Severity of illness measured by length of illness does not fully explain the lack of flexibility and supports the trait nature of inflexibility in people with AN.

A systematic review and meta-analysis of the association between depression and insulin resistance.

OBJECTIVE Depression is associated with the onset of type 2 diabetes. A systematic review and meta-analysis of observational studies, controlled trials, and unpublished data was conducted to examine the association between depression and insulin resistance (IR). RESEARCH DESIGN AND METHODS Medline, EMBASE, and PsycINFO were searched for studies published up to September 2011. Two independent reviewers assessed the eligibility of each report based on predefined inclusion criteria (study design and measure of depression and IR, excluding prevalent cases of diabetes). Individual effect sizes were standardized, and a meta-analysis was performed to calculate a pooled effect size using random effects. Subgroup analyses and meta-regression were conducted to explore any potential source of heterogeneity between studies. RESULTS Of 967 abstracts reviewed, 21 studies met the inclusion criteria of which 18 studies had appropriate data for the meta-analysis (n = 25,847). The pooled effect size (95% CI) was 0.19 (0.11–0.27) with marked heterogeneity (I2 = 82.2%) using the random-effects model. Heterogeneity between studies was not explained by age or sex, but could be partly explained by the methods of depression and IR assessments. CONCLUSIONS A small but significant cross-sectional association was observed between depression and IR, despite heterogeneity between studies. The pathophysiology mechanisms and direction of this association need further study using a purposively designed prospective or intervention study in samples at high risk for diabetes.