International review of neurobiology
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Int. Rev. Neurobiol. · Jan 2018
ReviewOptimizing Placebo and Minimizing Nocebo to Reduce Pain, Catastrophizing, and Opioid Use: A Review of the Science and an Evidence-Informed Clinical Toolkit.
Pain, a noxious psychosensory experience, motivates escape behavior to assure protection and survival. Psychological factors alter the experience and trajectory of pain, as well as behavior and treatment response. In the context of pain, the placebo effect (expectation for pain relief) releases endogenous opioids and facilitates analgesia from exogenously administered opioids. ⋯ Interventions that minimize nocebo and optimize placebo may adaptively shape the central nervous system toward pain relief and potentially opioid reduction. Here we provide a critical description of catastrophizing and its impact on pain, placebo and nocebo effects. We also consider the importance of minimizing nocebo and optimizing placebo effects during prescription opioid tapering, and offer a clinical toolkit of resources to accomplish these goals clinically.
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Int. Rev. Neurobiol. · Jan 2018
Nocebo Responses in Brain Diseases: A Systematic Review of the Current Literature.
Placebo is an intervention with no therapeutic effect that is used as a control in randomized controlled trials (RCTs). Placebo effects and responses can produce a beneficial effect that cannot be attributed to the properties of the intervention itself, since it is usually inactive, and should, therefore, be due to the patient's expectations about treatment (placebo effects), or confounding factors such as natural history, co-interventions, biases, among other co-factors (placebo responses). However, adverse events (AEs) may occur when using a placebo intervention, a phenomenon that is called nocebo. ⋯ Pooled dropout rates because of AEs in the placebo groups (i.e., nocebo dropout rates) vary from 2% in multiple sclerosis RCTs to almost 10% in PD RCTs. Across all brain disorders, the nature of AEs reported in the placebo-treated subjects mirrors those reported by active drug-treated subjects, suggesting that awareness of drug side-effect profiles might have influenced patient expectations and, thus, nocebo responses. Unexplored brain diseases where nocebo should be studied further include mental disorders (i.e., schizophrenia and bipolar disorder), vascular disorders (i.e., acute ischemic stroke, vascular dementia), degenerative disorders (i.e., frontotemporal dementia, Lewy body dementia) and other systemic atrophies of the brain (i.e., hereditary ataxias).
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Int. Rev. Neurobiol. · Jan 2016
ReviewGut-to-Brain Axis in Autism Spectrum Disorders: Central Role for the Microbiome.
Autism spectrum disorders (ASDs) are neurodevelopmental disorders, which occur in early childhood and persist into adulthood. Although the etiology of these disorders is largely unknown, genetic and environmental factors are thought to interplay in the development of ASD. ⋯ In this review, we address the clinical and preclinical findings on the role of the intestinal microbiome in ASD and suggest possible underlying mechanisms. Furthermore, opportunities for (nutritional) interventions in ASD are provided.
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Int. Rev. Neurobiol. · Jan 2016
ReviewGut Microbiome and Behavior: Focus on Neuroimmune Interactions.
As neuroscientists, psychologists, and psychiatrists are starting to appreciate the importance of the gut microbiota to mental health, it is critical to determine the mechanisms of microbiota to brain communication and thereby provide a better understanding of the aspects that may be modifiable with proper intervention in individuals with mental illness. Microbiota-brain communication is emerging as an important factor in brain development and function. ⋯ This chapter provides a review of the literature related to the influence of microbiota-immune-brain communication to behavior. This research has a clear translational relevance for mental health, contributing to extant findings that indicate a role for the microbiome in brain development and behavior.
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Int. Rev. Neurobiol. · Jan 2015
ReviewEvidence for a Role of Adolescent Endocannabinoid Signaling in Regulating HPA Axis Stress Responsivity and Emotional Behavior Development.
Adolescence is a period characterized by many distinct physical, behavioral, and neural changes during the transition from child- to adulthood. In particular, adolescent neural changes often confer greater plasticity and flexibility, yet with this comes the potential for heightened vulnerability to external perturbations such as stress exposure or recreational drug use. There is substantial evidence to suggest that factors such as adolescent stress exposure have longer lasting and sometimes more deleterious effects on an organism than stress exposure during adulthood. ⋯ Therefore, this review will focus on (1) the functionality of the adolescent HPA axis, (2) eCB regulation of the adult HPA axis, (3) dynamic changes in eCB signaling during the adolescent period, (4) the effects of adolescent stress exposure on the eCB system, and (5) modulation of HPA axis activity and emotional behavior by adolescent cannabinoid treatment. Collectively, the emerging picture suggests that the eCB system mediates interactions between HPA axis stress responsivity, emotionality, and maturational stage. These findings may be particularly relevant to our understanding of the development of affective disorders and the risks of adolescent cannabis consumption on emotional health and stress responsivity.