How placebos change the patient's brain

Plasma noradrenaline and state anxiety levels predict placebo response in learned immunosuppression

Large interindividual differences exist in the presence and extent of placebo responses in both experimental and clinical studies, but little is known about possible predictors of these responses. We employed a behaviorally conditioned immunosuppression paradigm in healthy men to analyze predictors of learned placebo responses. During acquisition, the subjects received either the immunosuppressant cyclosporin A (n = 32) or a placebo (n = 14) (unconditioned stimuli (US)) together with a novel-tasting drink (conditioned stimulus (CS)). During evocation, the subjects were reexposed to the CS alone. In responders (n = 15), the CS alone caused a significant inhibition of interleukin (IL)-2 production by anti-CD3-stimulated peripheral blood T cells, closely mimicking the drug effect. Nonresponders (n = 17) did not show responses different from those of the controls. Multiple-regression analyses showed that baseline IL-2, plasma noradrenaline, and state anxiety predicted nearly 60% of the variance in the conditioned IL-2 response. These data provide first evidence for putative biological and psychological predictors of learned placebo responses.

Brain-immune interactions and the neural basis of disease-avoidant ingestive behaviour

Neuro-immune interactions are widely manifested in animal physiology. Since immunity competes for energy with other physiological functions, it is subject to a circadian trade-off between other energy-demanding processes, such as neural activity, locomotion and thermoregulation. When immunity is challenged, this trade-off is tilted to an adaptive energy protecting and reallocation strategy that is identified as 'sickness behaviour'. We review diverse disease-avoidant behaviours in the context of ingestion, indicating that several adaptive advantages have been acquired by animals (including humans) during phylogenetic evolution and by ontogenetic experiences: (i) preventing waste of energy by reducing appetite and consequently foraging/hunting (illness anorexia), (ii) avoiding unnecessary danger by promoting safe environments (preventing disease encounter by olfactory cues and illness potentiation neophobia), (iii) help fighting against pathogenic threats (hyperthermia/somnolence), and (iv) by associative learning evading specific foods or environments signalling danger (conditioned taste avoidance/aversion) and/or at the same time preparing the body to counteract by anticipatory immune responses (conditioning immunomodulation). The neurobiology behind disease-avoidant ingestive behaviours is reviewed with special emphasis on the body energy balance (intake versus expenditure) and an evolutionary psychology perspective.

Evaluation of the effects of rivastigmine on cigarette smoking by methamphetamine-dependent volunteers

Compared to smokers alone, smokers with co-morbid substance use disorders are at greater risk of suffering from smoking-related death. Despite this, relatively few studies have examined smoking cessation treatments for those with stimulant dependence. In the current study, we sought to evaluate the effects produced by short-term exposure to the cholinesterase inhibitor rivastigmine (0, 3 or 6 mg) on cigarette smoking in non-treatment-seeking, methamphetamine-dependent volunteers. This was a double-blind, placebo-controlled, crossover study that took place over 9 days. The data indicate that rivastigmine treatment did not alter Fagerström Test for Nicotine Dependence scores, carbon monoxide readings, or cigarettes smoked per day, but a trend toward reduced urges to smoke (p<0.09) was detected during treatment with rivastigmine 3mg. These data, while preliminary, indicate that cholinesterase inhibitors warrant consideration as treatments for nicotine dependence, including use in stimulant-dependent individuals who exhibit significantly higher rates of smoking than the general population.

Placebo mechanisms across different conditions: from the clinical setting to physical performance

Although the great increase in interest in the placebo phenomenon was spurred by the clinical implications of its use, the progressive elucidation of the neurobiological and pharmacological mechanisms underlying the placebo effect also helps cast new light on the relationship between mind (and brain) and body, a topic of foremost philosophical importance but also a major medical issue in light of the complex interactions between the brain on the one hand and body functions on the other. While the concept of placebo can be a general one, with a broad definition generally applicable to many different contexts, the description of the cerebral processes called into action in specific situations can vary widely. In this paper, examples will be given where physiological or pathological conditions are altered following the administration of an inert substance or verbal instructions tailored to induce expectation of a change, and explanations will be offered with details on neurotransmitter changes and neural pathways activated. As an instance of how placebo effects can extend beyond the clinical setting, data in the physical performance domain and implications for sport competitions will also be presented and discussed.

Deep hope: a song without words

Hope helps alleviate suffering. In the case of terminal illness, recent experience in palliative medicine has taught physicians that hope is durable and often thrives even in the face of imminent death. In this article, I examine the perspectives of philosophers, theologians, psychologists, clinicians, neuroscientists, and poets, and provide a series of observations, connections, and gestures about hope, particularly about what I call "deep hope." I end with some proposals about how such hope can be sustained and enhanced at the end of life. Studies of terminally ill patients have revealed clusters of personal and situational factors associated with enhancement or suppression of hope at the end of life. Interpersonal connectedness, attainable goals, spiritual beliefs and practices, personal attributes of determination, courage, and serenity, lightheartedness, uplifting memories, and affirmation of personal worth enhance hope, while uncontrollable pain and discomfort, abandonment and isolation, and devaluation of personhood suppress hope. I suggest that most of these factors can be modulated by good medical care, utilizing basic interpersonal techniques that demonstrate kindness, humanity, and respect.

Role of central neurophysiological systems in placebo analgesia and their relationships with cognitive processes mediating placebo responding

The harnessing of the positive aspects of the placebo effect in clinical practice is a major clinical and ethical challenge, and requires better understanding of placebo mechanisms. In this article, we present an explanatory cognitive model of placebo analgesia, centered on expectation of pain relief, and present direct and indirect evidence for the psychological and physiological drivers and downstream mediators of the effects of expectation on reduction in pain. The endogenous opioid system is involved in expectation-mediated analgesia, but it is not known whether this system is required for the generation or downstream effects of expectation. There is indirect evidence to support the role of other neurotransmitter systems, such as the serotonergic and dopamine systems, and a possible role of the hypothalamic–pituitary–adrenal stress axis. The future challenge is the identification of the causal role of these systems in placebo analgesia, which would provide an empirical basis for exploring new pain therapies.

Placebo response in clinical trials with schizophrenia patients

PURPOSE OF REVIEW

The magnitude of placebo response is an important factor in the outcome of clinical trials, in that excessive placebo response can obscure true drug-placebo differences. There is ample evidence of the impact of elevated placebo response in trials of major depression, but less intensive research has been done in the area of schizophrenia. We present a current review of placebo response in clinical trials of schizophrenia.

RECENT FINDINGS

The existing evidence suggests that placebo response in schizophrenia trials may be similar in magnitude, quality, and impact to that observed in depression trials, and has similarly increased over the past several years. We discuss factors influencing excessive placebo response during the conduct of clinical trials and how they may be managed to help minimize placebo response.

SUMMARY

There does not appear to be any single major factor contributing to the high levels of placebo response in schizophrenia clinical trials; therefore, a multipronged approach to minimizing excessive placebo response or its impact is recommended.

Bridging the Valley of Death of therapeutics for neurodegeneration

Neurodegenerative diseases are the sixth leading cause of death in the US. The market for disease-modifying drugs is enormous, but no drug exists. Academic scientists are increasingly pursuing the discovery and development of therapeutics. Their progress could potentially reduce the risk of failure sufficiently to warrant greater industry investment and movement of leads into clinical trials. Here we consider the many obstacles to the development of therapeutics for neurodegenerative disease within academia, with a special focus on organizational issues.