Evidence-based umbrella review of 162 peripheral biomarkers for major mental disorders

The literature on non-genetic peripheral biomarkers for major mental disorders is broad, with conflicting results. An umbrella review of meta-analyses of non-genetic peripheral biomarkers for Alzheimer's disease, autism spectrum disorder, bipolar disorder (BD), major depressive disorder, and schizophrenia, including first-episode psychosis. We included meta-analyses that compared alterations in peripheral biomarkers between participants with mental disorders to controls (i.e., between-group meta-analyses) and that assessed biomarkers after treatment (i.e., within-group meta-analyses). Evidence for association was hierarchically graded using a priori defined criteria against several biases. The Assessment of Multiple Systematic Reviews (AMSTAR) instrument was used to investigate study quality. 1161 references were screened. 110 met inclusion criteria, relating to 359 meta-analytic estimates and 733,316 measurements, on 162 different biomarkers. Only two estimates met a priori defined criteria for convincing evidence (elevated awakening cortisol levels in euthymic BD participants relative to controls and decreased pyridoxal levels in participants with schizophrenia relative to controls). Of 42 estimates which met criteria for highly suggestive evidence only five biomarker aberrations occurred in more than one disorder. Only 15 meta-analyses had a power >0.8 to detect a small effect size, and most (81.9%) meta-analyses had high heterogeneity. Although some associations met criteria for either convincing or highly suggestive evidence, overall the vast literature of peripheral biomarkers for major mental disorders is affected by bias and is underpowered. No convincing evidence supported the existence of a trans-diagnostic biomarker. Adequately powered and methodologically sound future large collaborative studies are warranted.

Environmental risk factors and nonpharmacological and nonsurgical interventions for obesity: An umbrella review of meta-analyses of cohort studies and randomized controlled trials

BACKGROUND

Multiple environmental factors have been implicated in obesity, and multiple interventions, besides drugs and surgery, have been assessed in obese patients. Results are scattered across many studies and meta-analyses, and they often mix obese and overweight individuals.

MATERIALS AND METHODS

PubMed and Cochrane Database of Systematic Reviews were searched through 21 January 2017 for meta-analyses of cohort studies assessing environmental risk factors for obesity, and randomized controlled trials investigating nonpharmacological and nonsurgical therapeutic interventions for obesity. We excluded data on overweight participants. Evidence from observational studies was graded according to criteria that included the statistical significance of the random-effects summary estimate and of the largest study in a meta-analysis, the number of obesity cases, heterogeneity between studies, 95% prediction intervals, small-study effects and excess significance. The evidence of intervention studies for obesity was assessed with the GRADE framework.

RESULTS

Fifty-four articles met eligibility criteria, including 26 meta-analyses of environmental risk factors (166 studies) and 46 meta-analyses of nondrug, nonsurgical interventions (206 trials). In adults, the only risk factor with convincing evidence was depression, and childhood obesity, adolescent obesity, childhood abuse and short sleep duration had highly suggestive evidence. Infancy weight gain during the first year of life, depression and low maternal education had convincing evidence for association with paediatric obesity. All interventions had low or very-low-quality evidence with one exception of moderate-quality evidence for one comparison (no differences in efficacy between brief lifestyle primary care interventions and other interventions for paediatric obesity). Summary effect sizes were mostly small across compared interventions (maximum 5.1 kg in adults and 1.78 kg in children) and even these estimates may be inflated.

CONCLUSIONS

Depression, obesity in earlier age groups, short sleep duration, childhood abuse and low maternal education have the strongest support among proposed risk factors for obesity. Furthermore, there is no high-quality evidence to recommend treating obesity with a specific nonpharmacological and nonsurgical intervention among many available, and whatever benefits in terms of magnitude of weight loss appear small.

Mapping risk factors for depression across the lifespan: An umbrella review of evidence from meta-analyses and Mendelian randomization studies

The development of depression may involve a complex interplay of environmental and genetic risk factors. PubMed and PsycInfo databases were searched from inception through August 3, 2017, to identify meta-analyses and Mendelian randomization (MR) studies of environmental risk factors associated with depression. For each eligible meta-analysis, we estimated the summary effect size and its 95% confidence interval (CI) by random-effects modeling, the 95% prediction interval, heterogeneity with I², and evidence of small-study effects and excess significance bias. Seventy meta-analytic reviews met the eligibility criteria and provided 134 meta-analyses for associations from 1283 primary studies. While 109 associations were nominally significant (P < 0.05), only 8 met the criteria for convincing evidence and, when limited to prospective studies, convincing evidence was found in 6 (widowhood, physical abuse during childhood, obesity, having 4-5 metabolic risk factors, sexual dysfunction, job strain). In studies in which depression was assessed through a structured diagnostic interview, only associations with widowhood, job strain, and being a Gulf War veteran were supported by convincing evidence. Additionally, 8 MR studies were included and provided no consistent evidence for the causal effects of obesity, smoking, and alcohol consumption. The proportion of variance explained by genetic risk factors was extremely small (0.1-0.4%), which limited the evidence provided by the MR studies. Our findings suggest that despite the large number of putative risk factors investigated in the literature, few associations were supported by robust evidence. The current findings may have clinical and research implications for the early identification of individuals at risk for depression.

Prevalence, incidence and mortality from cardiovascular disease in patients with pooled and specific severe mental illness: a large-scale meta-analysis of 3,211,768 patients and 113,383,368 controls

People with severe mental illness (SMI) - schizophrenia, bipolar disorder and major depressive disorder - appear at risk for cardiovascular disease (CVD), but a comprehensive meta-analysis is lacking. We conducted a large-scale meta-analysis assessing the prevalence and incidence of CVD; coronary heart disease; stroke, transient ischemic attack or cerebrovascular disease; congestive heart failure; peripheral vascular disease; and CVD-related death in SMI patients (N=3,211,768) versus controls (N=113,383,368) (92 studies). The pooled CVD prevalence in SMI patients (mean age 50 years) was 9.9% (95% CI: 7.4-13.3). Adjusting for a median of seven confounders, patients had significantly higher odds of CVD versus controls in cross-sectional studies (odds ratio, OR=1.53, 95% CI: 1.27-1.83; 11 studies), and higher odds of coronary heart disease (OR=1.51, 95% CI: 1.47-1.55) and cerebrovascular disease (OR=1.42, 95% CI: 1.21-1.66). People with major depressive disorder were at increased risk for coronary heart disease, while those with schizophrenia were at increased risk for coronary heart disease, cerebrovascular disease and congestive heart failure. Cumulative CVD incidence in SMI patients was 3.6% (95% CI: 2.7-5.3) during a median follow-up of 8.4 years (range 1.8-30.0). Adjusting for a median of six confounders, SMI patients had significantly higher CVD incidence than controls in longitudinal studies (hazard ratio, HR=1.78, 95% CI: 1.60-1.98; 31 studies). The incidence was also higher for coronary heart disease (HR=1.54, 95% CI: 1.30-1.82), cerebrovascular disease (HR=1.64, 95% CI: 1.26-2.14), congestive heart failure (HR=2.10, 95% CI: 1.64-2.70), and CVD-related death (HR=1.85, 95% CI: 1.53-2.24). People with major depressive disorder, bipolar disorder and schizophrenia were all at increased risk of CVD-related death versus controls. CVD incidence increased with antipsychotic use (p=0.008), higher body mass index (p=0.008) and higher baseline CVD prevalence (p=0.03) in patients vs.

CONTROLS

Moreover, CVD prevalence (p=0.007), but not CVD incidence (p=0.21), increased in more recently conducted studies. This large-scale meta-analysis confirms that SMI patients have significantly increased risk of CVD and CVD-related mortality, and that elevated body mass index, antipsychotic use, and CVD screening and management require urgent clinical attention.

Systematic assessment of environmental risk factors for bipolar disorder: an umbrella review of systematic reviews and meta-analyses

OBJECTIVES

The pathophysiology of bipolar disorder is likely to involve both genetic and environmental risk factors. In our study, we aimed to perform a systematic search of environmental risk factors for BD. In addition, we assessed possible hints of bias in this literature, and identified risk factors supported by high epidemiological credibility.

METHODS

We searched the Pubmed/MEDLINE, EMBASE and PsycInfo databases up to 7 October 2016 to identify systematic reviews and meta-analyses of observational studies that assessed associations between putative environmental risk factors and BD. For each meta-analysis, we estimated its summary effect size by means of both random- and fixed-effects models, 95% confidence intervals (CIs), the 95% prediction interval, and heterogeneity. Evidence of small-study effects and excess of significance bias was also assessed.

RESULTS

Sixteen publications met the inclusion criteria (seven meta-analyses and nine qualitative systematic reviews). Fifty-one unique environmental risk factors for BD were evaluated. Six meta-analyses investigated associations with a risk factor for BD. Only irritable bowel syndrome (IBS) emerged as a risk factor for BD supported by convincing evidence (k=6; odds ratio [OR]=2.48; 95% CI=2.35-2.61; P<.001), and childhood adversity was supported by highly suggestive evidence. Asthma and obesity were risk factors for BD supported by suggestive evidence, and seropositivity to Toxoplasma gondii and a history of head injury were supported by weak evidence.

CONCLUSIONS

Notwithstanding that several environmental risk factors for BD were identified, few meta-analyses of observational studies were available. Therefore, further well-designed and adequately powered studies are necessary to map the environmental risk factors for BD.

Depression in cancer: The many biobehavioral pathways driving tumor progression

Major Depressive Disorder (MDD) is common among cancer patients, with prevalence rates up to four-times higher than the general population. Depression confers worse outcomes, including non-adherence to treatment and increased mortality in the oncology setting. Advances in the understanding of neurobiological underpinnings of depression have revealed shared biobehavioral mechanisms may contribute to cancer progression. Moreover, psychosocial stressors in cancer promote: (1) inflammation and oxidative/nitrosative stress; (2) a decreased immunosurveillance; and (3) a dysfunctional activation of the autonomic nervous system and of the hypothalamic-pituitaryadrenal axis. Consequently, the prompt recognition of depression among patients with cancer who may benefit of treatment strategies targeting depressive symptoms, cognitive dysfunction, fatigue and sleep disturbances, is a public health priority. Moreover, behavioral strategies aiming at reducing psychological distress and depressive symptoms, including addressing unhealthy diet and life-style choices, as well as physical inactivity and sleep dysfunction, may represent important strategies not only to treat depression, but also to improve wider cancer-related outcomes. Herein, we provide a comprehensive review of the intertwined biobehavioral pathways linking depression to cancer progression. In addition, the clinical implications of these findings are critically reviewed.

The Involvement of TNF-α in Cognitive Dysfunction Associated with Major Depressive Disorder: An Opportunity for Domain Specific Treatments

Major depressive disorder is a highly prevalent, chronic and recurring disorder, associated with substantial impairment in cognitive and interpersonal functions. Accumulating evidence suggests that inflammatory processes play an important role in the etio-pathogenesis, phenomenology, comorbidity and treatment of MDD. Suboptimal remission rates and the persistence of cognitive deficits contribute to functional impairment in MDD inviting the need for the development of mechanistically novel and domain specific treatment approaches. The MEDLINE/ Pubmed database was searched from inception to February, 9^th, 2014 with combinations of the following search terms: ‘TNF-alpha’, ‘depression’, ‘infliximab’, ‘etanercept’, ‘adalimumab’, ‘golimumab’and ‘certolizumab’. Preclinical and clinical evidence linking TNF-α to MDD pathophysiology were reviewed as well as the current status of TNF-α modulators as novel agents for the treatment of MDD. Experimental models and clinical studies provide encouraging preliminary evidence for the efficacy of TNF-α antagonists in mitigating depressive symptoms and improving cognitive deficits. Further studies are warranted to confirm these data in larger randomized controlled trials in primary psychiatric populations. Translational research provides a promising perspective that may aid the development and/or repurposing of mechanism-based treatments for depressive symptoms and cognitive impairment in MDD.

Cognitive dysfunction in major depressive disorder: a state-of-the-art clinical review

Major depressive disorder (MDD) is a prevalent and recurring mental disorder often associated with high rates of non-recovery and substantial consequences on psychosocial outcome. Cognitive impairment is one of the most frequent residual symptoms of MDD. The persistence of cognitive impairment even in remitted phases of the disorder, notably in the domains of executive function and attention, suggests that it may serve as a mediational nexus between MDD and poor functional outcome, accounting for occupational and relational difficulties regardless of clinical improvement on depressive symptoms. The critical impact of cognitive deficits on psychosocial dysfunction invites clinicians to regularly screen and assess cognition across multiple domains, taking into account also clinical correlates of cognitive dysfunction in MDD. Despite the availability of several instruments for the screening and assessment of cognitive dysfunction, the lack of consensus guiding the choice of appropriate instruments increases the likelihood to underestimate cognitive dysfunction in MDD in clinical settings. On the other hand, the unsatisfactory effect of most antidepressant treatments on cognitive deficits for many individuals with MDD calls for the development of genuinely novel therapeutic agents with potential to target cognitive dysfunction. Notwithstanding the necessity of further investigations, this review indicates that neuropsychological deficits (e.g., impaired executive functions) are stable markers of MDD and underscores the need for the development of integrative and multi-modal strategies for the prevention and treatment of neuropsychological impairments in MDD.

Cognitive dysfunction in bipolar disorder and schizophrenia: a systematic review of meta-analyses

Cognitive impairment is a core feature of schizophrenia (SZ) and bipolar disorder (BD). A neurocognitive profile characterized by widespread cognitive deficits across multiple domains in the context of substantial intellectual impairment, which appears to antedate illness onset, is a replicated finding in SZ. There is no specific neuropsychological signature that can facilitate the diagnostic differentiation of SZ and BD, notwithstanding, neuropsychological deficits appear more severe in SZ. The literature in this field has provided contradictory results due to methodological differences across studies. Meta-analytic techniques may offer an opportunity to synthesize findings and to control for potential sources of heterogeneity. Here, we performed a systematic review of meta-analyses of neuropsychological findings in SZ and BD. While there is no conclusive evidence for progressive cognitive deterioration in either SZ or BD, some findings point to more severe cognitive deficits in patients with early illness onset across both disorders. A compromised pattern of cognitive functioning in individuals at familiar and/or clinical risk to psychosis as well as in first-degree relatives of BD patients suggests that early neurodevelopmental factors may play a role in the emergence of cognitive deficits in both disorders. Premorbid intellectual impairment in SZ and at least in a subgroup of patients with BD may be related to a shared genetically determined influence on neurodevelopment.

Micronuclei in cytokinesis-blocked lymphocytes may predict patient response to radiotherapy

We have applied the cytokinesis-block micronucleus assay to peripheral blood lymphocytes of patients undergoing radiotherapy in pelvic and pulmonary sites, in order to evaluate the individual cytogenetic response. Our cytogenetic data correlated with the equivalent whole-body dose are homogeneous and compare well with the data presented by other authors. We have used an exponential mathematical formula to calculate the attenuation of the cytogenetic effect with time. The k coefficient (cytogenetic recovery factor) in the formula expresses the degree of attenuation. In lymphocytes from patients after radiotherapy, the trend of the micronucleus frequency observed after 2 Gy of in vitro X-irradiation demonstrates that the cytogenetic effect obtained in vitro is added to that obtained in vivo. The k coefficient is inversely proportional to the micronucleus frequency observed after 2 Gy in vitro. The micronucleus assay and the cytogenetic recovery factor are proposed as suitable diagnostic tools for application in the field of radiotherapy.