A nocebo effect is said to occur when a patient's negative expectations for a treatment cause the treatment to have a worse effect than it otherwise would have. [1] [2] For example, when a patient anticipates a side effect of a medication, they can experience that effect even if the "medication" is actually an inert substance. [1] The complementary concept, the placebo effect, is said to occur when positive expectations improve an outcome. The nocebo effect is also said to occur in someone who falls ill owing to the erroneous belief that they were exposed to a physical phenomenon they believe is harmful, such as EM radiation. [3]
Both placebo and nocebo effects are presumably psychogenic, but they can induce measurable changes in the body. [1] One article that reviewed 31 studies on nocebo effects reported a wide range of symptoms that could manifest as nocebo effects, including nausea, stomach pains, itching, bloating, depression, sleep problems, loss of appetite, sexual dysfunction, and severe hypotension. [1]
Walter Kennedy coined the term nocebo (Latin nocēbō , "I shall harm", from noceō , "I harm") [4] in 1961 to denote the counterpart of placebo (Latin placēbō , "I shall please", from placeō , "I please"), [5] a substance that may produce a beneficial, healthful, pleasant, or desirable effect. Kennedy emphasized that his use of the term nocebo refers strictly to a subject-centered response, a quality "inherent in the patient rather than in the remedy". [6] That is, he rejected the use of the term for pharmacologically induced negative side effects such as the ringing in the ears caused by quinine. [6] That is not to say that the patient's psychologically induced response may not include physiological effects. For example, an expectation of pain may induce anxiety, which in turn causes the release of cholecystokinin, which facilitates pain transmission. [7]
In the narrowest sense, a nocebo response occurs when a drug-trial subject's symptoms are worsened by the administration of an inert, sham, [8] or dummy (simulator) treatment, called a placebo. Placebos contain no chemicals (or any other agents) that could cause any of the observed worsening in the subject's symptoms, so any change for the worse must be due to some subjective factor. Adverse expectations can also cause anesthetic medications' analgesic effects to disappear. [9]
The worsening of the subject's symptoms or reduction of beneficial effects is a direct consequence of their exposure to the placebo, but the placebo has not chemically generated those symptoms. Because this generation of symptoms entails a complex of "subject-internal" activities, we can never speak in the strictest sense in terms of simulator-centered "nocebo effects", but only in terms of subject-centered "nocebo responses". Some observers attribute nocebo responses (or placebo responses) to a subject's gullibility, but there is no evidence that someone who manifests a nocebo/placebo response to one treatment will manifest a nocebo/placebo response to any other treatment; i.e., there is no fixed nocebo/placebo-responding trait or propensity. [10]
McGlashan, Evans & Orne found no evidence in 1969 of what they termed a placebo personality. [11] In 1954, Lasagna, Mosteller, von Felsinger, and Beecher [12] found in a carefully designed study that there was no way that any observer could determine, by testing or by interview, which subjects would manifest placebo reactions and which would not. Experiments have shown that no relationship exists between an person's measured hypnotic susceptibility and their manifestation of nocebo or placebo responses. [13] [14] [15]
Based on a biosemiotic model (2022), Goli explains how harm and/or healing expectations lead to a multimodal image and form transient allostatic or homeostatic interoceptive feelings, demonstrating how repetitive experiences of a potential body induce epigenetic changes and form new attractors, such as nocebos and placeboes, in the actual body. [16]
It has been shown that, due to the nocebo effect, warning patients about drugs' side effects can contribute to the causation of such effects, whether the drug is real or not. [17] [18] This effect has been observed in clinical trials: according to a 2013 review, the dropout rate among placebo-treated patients in a meta-analysis of 41 clinical trials of Parkinson's disease treatments was 8.8%. [19] A 2013 review found that nearly 1 out of 20 patients receiving a placebo in clinical trials for depression dropped out due to adverse events, which were believed to have been caused by the nocebo effect. [20]
In January 2022, a systematic review and meta-analysis concluded that nocebo responses accounted for 72% of adverse effects after the first COVID-19 vaccine dose and 52% after the second dose. [21] [22]
Many studies show that the formation of nocebo responses are influenced by inappropriate health education, media work, and other discourse makers who induce health anxiety and negative expectations. [23]
Evidence suggests that the symptoms of electromagnetic hypersensitivity are caused by the nocebo effect. [24] [25]
Verbal suggestion can cause hyperalgesia (increased sensitivity to pain) and allodynia (perception of a tactile stimulus as painful) as a result of the nocebo effect. [26] Nocebo hyperalgesia is believed to involve the activation of cholecystokinin receptors. [27]
Stewart-Williams and Podd argue that using the contrasting terms "placebo" and "nocebo" for inert agents that produce pleasant, health-improving, or desirable outcomes and unpleasant, health-diminishing, or undesirable outcomes (respectively) is extremely counterproductive. [28] For example, precisely the same inert agents can produce analgesia and hyperalgesia, the first of which, on this definition, would be a placebo, and the second a nocebo. [29]
A second problem is that the same effect, such as immunosuppression, may be desirable for a subject with an autoimmune disorder, but undesirable for most other subjects. Thus, in the first case, the effect would be a placebo, and in the second a nocebo. [28] A third problem is that the prescriber does not know whether the relevant subjects consider the effects they experience desirable or undesirable until some time after the drugs have been administered. [28] A fourth is that the same phenomena are generated in all the subjects, and generated by the same drug, which is acting in all of the subjects through the same mechanism. Yet because the phenomena in question have been subjectively considered desirable to one group but not the other, the phenomena are now being labeled in two mutually exclusive ways (i.e., placebo and nocebo), giving the false impression that the drug in question has produced two different phenomena. [28]
Some people maintain that belief can kill (e.g., voodoo death: Cannon in 1942 describes a number of instances from a variety of different cultures) and or heal (e.g., faith healing). [30] A self-willed death (due to voodoo hex, evil eye, pointing the bone procedure, [31] [32] etc.) is an extreme form of a culture-specific syndrome or mass psychogenic illness that produces a particular form of psychosomatic or psychophysiological disorder resulting in psychogenic death. Rubel in 1964 spoke of "culture-bound" syndromes, those "from which members of a particular group claim to suffer and for which their culture provides an etiology, diagnosis, preventive measures, and regimens of healing". [33]
Certain anthropologists, such as Robert Hahn and Arthur Kleinman, have extended the placebo/nocebo distinction into this realm to allow a distinction to be made between rituals, such as faith healing, performed to heal, cure, or bring benefit (placebo rituals) and others, such as "pointing the bone", performed to kill, injure or bring harm (nocebo rituals). As the meaning of the two interrelated and opposing terms has extended, we now find anthropologists speaking, in various contexts, of nocebo or placebo (harmful or helpful) rituals: [34]
Yet it may become even more terminologically complex, for as Hahn and Kleinman indicate, there can also be cases of paradoxical nocebo outcomes from placebo rituals and placebo outcomes from nocebo rituals (see also unintended consequences). [34] In 1973, writing from his extensive experience of treating cancer (including more than 1,000 melanoma cases) at Sydney Hospital, Milton warned of the impact of the delivery of a prognosis, and how many of his patients, upon receiving their prognosis, simply turned their face to the wall and died a premature death: "there is a small group of patients in whom the realization of impending death is a blow so terrible that they are quite unable to adjust to it, and they die rapidly before the malignancy seems to have developed enough to cause death. This problem of self-willed death is in some ways analogous to the death produced in primitive peoples by witchcraft ('pointing the bone')". [35]
Some researchers have pointed out that the harm caused by communicating with patients about potential treatment adverse events raises an ethical issue. To respect their autonomy, one must inform a patient about harms a treatment may cause. Yet the way in which potential harms are communicated could cause additional harm, which may violate the ethical principle of non-maleficence. [36] It is possible that nocebo effects can be reduced while respecting autonomy using different models of informed consent, including the use of a framing effect [37] and the authorized concealment.
Psychosomatic medicine is an interdisciplinary medical field exploring the relationships among social, psychological, behavioral factors on bodily processes and quality of life in humans and animals.
A placebo is a substance or treatment which is designed to have no therapeutic value. Common placebos include inert tablets, inert injections, sham surgery, and other procedures.
Duloxetine, sold under the brand name Cymbalta among others, is a medication used to treat major depressive disorder, generalized anxiety disorder, obsessive-compulsive disorder, fibromyalgia, neuropathic pain and central sensitization. It is taken by mouth.
Nabiximols (USAN) sold under the brand name Sativex, is a specific Cannabis extract that was approved in 2010 as a botanical drug in the United Kingdom. Nabiximols is sold as a mouth spray intended to alleviate neuropathic pain, spasticity, overactive bladder, and other symptoms of multiple sclerosis; it was developed by the UK company GW Pharmaceuticals. In 2019, it was proposed that following application of the spray, nabiximols is washed away from the oral mucosa by the saliva flow and ingested into the stomach, with subsequent absorption from the gastro-intestinal tract. Nabiximols is a combination drug standardized in composition, formulation, and dose. Its principal active components are the cannabinoids: tetrahydrocannabinol (THC) and cannabidiol (CBD). Each spray delivers a dose of 2.7 mg THC and 2.5 mg CBD.
Pain disorder is chronic pain experienced by a patient in one or more areas, and is thought to be caused by psychological stress. The pain is often so severe that it disables the patient from proper functioning. Duration may be as short as a few days or as long as many years. The disorder may begin at any age, and occurs more frequently in girls than boys. This disorder often occurs after an accident, during an illness that has caused pain, or after withdrawing from use during drug addiction, which then takes on a 'life' of its own.
Primary polydipsia and psychogenic polydipsia are forms of polydipsia characterised by excessive fluid intake in the absence of physiological stimuli to drink. Psychogenic polydipsia caused by psychiatric disorders—oftentimes schizophrenia—is frequently accompanied by the sensation of dry mouth. Some conditions with polydipsia as a symptom are non-psychogenic. Primary polydipsia is a diagnosis of exclusion.
Medically unexplained physical symptoms are symptoms for which a treating physician or other healthcare providers have found no medical cause, or whose cause remains contested. In its strictest sense, the term simply means that the cause for the symptoms is unknown or disputed—there is no scientific consensus. Not all medically unexplained symptoms are influenced by identifiable psychological factors. However, in practice, most physicians and authors who use the term consider that the symptoms most likely arise from psychological causes. Typically, the possibility that MUPS are caused by prescription drugs or other drugs is ignored. It is estimated that between 15% and 30% of all primary care consultations are for medically unexplained symptoms. A large Canadian community survey revealed that the most common medically unexplained symptoms are musculoskeletal pain, ear, nose, and throat symptoms, abdominal pain and gastrointestinal symptoms, fatigue, and dizziness. The term MUPS can also be used to refer to syndromes whose etiology remains contested, including chronic fatigue syndrome, fibromyalgia, multiple chemical sensitivity and Gulf War illness.
Somatization is a tendency to experience and communicate psychological distress as bodily and organic symptoms and to seek medical help for them. More commonly expressed, it is the generation of physical symptoms of a psychiatric condition such as anxiety. The term somatization was introduced by Wilhelm Stekel in 1924.
Somatosensory amplification (SSA) is a tendency to perceive normal somatic and visceral sensations as being relatively intense, disturbing and noxious. It is a common feature of hypochondriasis and is commonly found with fibromyalgia, major depressive disorder, some anxiety disorders, Asperger syndrome, and alexithymia. One common clinical measure of SSA is the Somatosensory Amplification Scale (SSAS).
Classified as a "conversion disorder" by the DSM-IV, a psychogenic disease is a condition in which mental stressors cause physical symptoms matching other disorders. The manifestation of physical symptoms without biologically identifiable cause results from disruptions in normal brain function due to psychological stress. During a psychogenic episode, neuroimaging has shown that neural circuits affecting functions such as emotion, executive functioning, perception, movement, and volition are inhibited. These disruptions become strong enough to prevent the brain from voluntarily allowing certain actions. When the brain is unable to signal to the body to perform an action voluntarily, physical symptoms of a disorder arise. Examples of diseases that are deemed to be psychogenic in origin include psychogenic seizures, psychogenic polydipsia, psychogenic tremor, and psychogenic pain.
Proglumide, sold under the brand name Milid, is a drug that inhibits gastrointestinal motility and reduces gastric secretions. It acts as a cholecystokinin antagonist, which blocks both the CCKA and CCKB subtypes. It was used mainly in the treatment of stomach ulcers, although it has now been largely replaced by newer drugs for this application.
Itopride (INN; brand name Ganaton) is a prokinetic benzamide derivative. These drugs inhibit dopamine and acetylcholine esterase enzyme and have a gastrokinetic effect. Itopride is indicated for the treatment of functional dyspepsia and other gastrointestinal conditions. It is a combined D2 receptor antagonist and acetylcholinesterase inhibitor. Itopride is the dimethoxy analog of trimethobenzamide.
Psychogenic pain is physical pain that is caused, increased, or prolonged by mental, emotional, or behavioral factors, without evidence of physical injury or illness.
The health management system (HMS) is an evolutionary medicine regulative process proposed by Nicholas Humphrey in which actuarial assessment of fitness and economic-type cost–benefit analysis determine the body's regulation of its physiology and health. The incorporation of the cost–benefit calculations into body regulation provides a science grounded approach to mind–body phenomena such as placebos, are otherwise not explainable by low level, noneconomic, and purely feedback based homeostatic or allostatic theories.
The word placebo was used in a medicinal context in the late 18th century to describe a "commonplace method or medicine" and in 1811 it was defined as "any medicine adapted more to please than to benefit the patient". Although this definition contained a derogatory implication, it did not necessarily imply that the remedy had no effect.
Functional disorders are a group of recognisable medical conditions which are due to changes to the functioning of the systems of the body rather than due to a disease affecting the structure of the body.
Somatic symptom disorder, also known as somatoform disorder, or somatization disorder, is defined by one or more chronic physical symptoms that coincide with excessive and maladaptive thoughts, emotions, and behaviors connected to those symptoms. The symptoms are not deliberately produced or feigned, and they may or may not coexist with a known medical ailment.
Fabrizio Benedetti is professor of physiology and neuroscience at the University of Turin Medical School in Turin, Italy and a researcher in the field of placebo studies. He is known for his research into the placebo and nocebo effects.
Placebo analgesia occurs when the administration of placebos leads to pain relief. Because placebos by definition lack active ingredients, the effect of placebo analgesia is considered to result from the patient's belief that they are receiving an analgesic drug or other medical intervention. It has been shown that, in some cases, the endogenous opioid system is critical for mediating placebo analgesia, as evidenced by the ability of such analgesia to be reduced by the opioid antagonist naloxone. However, it is also possible for placebo analgesia to be mediated by non-opioid mechanisms, in which case it would not be affected by naloxone. Other research has indicated that the human spinal cord, prefrontal cortex, and rostral anterior cingulate cortex also play a role in placebo analgesia.
Winfried Rief (born 12 May 1959) is a German psychologist. Since 2000 he has been a professor of clinical psychology and psychotherapy at the University of Marburg. Rief's research examines the psychological factors involved in the development, maintenance and management of physical complaints, including investigations of somatic symptom disorders and placebo effects. Rief is the founding editor of the academic journal Clinical Psychology in Europe.