Treatment of last resort? Psychological therapy seeking in chronic pain patients.

OBJECTIVE: Our goal was to assess how many chronic pain patients seek psychological treatment for their condition and what psychological and demographic characteristics are associated with that decision. METHODS: The association between pain intensity, quality of life and psychological treatment seeking was tested in two hypothetical models which differed according to beliefs about either external or internal control over pain. RESULTS: A minority of patients had experience with psychological treatment of chronic pain. Patients who had that experience were younger, suffered from more intense pain, and applied many more coping strategies than patients who never tried this kind of treatment. Intense pain and low quality of life motivated chronic pain patients to seek psychological treatment only if they believed that doctors could control their pain. DISCUSSION: The study results stress the importance of diversifying the methods used to treat chronic pain and educating patients about the benefits of psychological treatment. Low numbers of chronic pain patients who take advantage of psychological treatment indicate that encouragement from medical professionals might be necessary.

Order does matter: the combined effects of classical conditioning and verbal suggestions on placebo hypoalgesia and nocebo hyperalgesia.

ABSTRACT: In most experimental studies in which verbal suggestion and classical conditioning are implemented together to induce placebo effects, the former precedes the latter. In naturally occurring situations, however, the information concerning pain does not always precede but often follows the pain experience. Moreover, this information is not always congruent with experience. This study investigates whether the chronology of verbal suggestion and conditioning, as well as their congruence, affects placebo hypoalgesia and nocebo hyperalgesia. The effects induced in 15 groups were compared. The participants in 8 experimental groups were presented with verbal suggestions that were either congruent or incongruent with classical conditioning. The verbal suggestions were provided either before or after conditioning. In 2 other experimental groups, placebo conditioning or nocebo conditioning was implemented without any verbal suggestion; in 2 groups, verbal suggestion of hypoalgesia or hyperalgesia without conditioning was applied. The control groups without any suggestions or conditioning were also included. Placebo hypoalgesia induced by congruent procedures was significantly stronger when the suggestion of hypoalgesia preceded rather than followed conditioning. The order of the congruent procedures did not affect the magnitude of nocebo hyperalgesia. In the groups in which incongruent procedures were implemented, placebo hypoalgesia or nocebo hyperalgesia was in line with the direction of the last-used procedure, regardless of whether it was conditioning or verbal suggestion. The results show that not the type of the procedure (verbal suggestion or conditioning), but the direction of the last-used procedure shapes pain-related expectancies and determines placebo effects.

One of us or one of them? The effects of the model's and observer's characteristics on placebo analgesia induced by observational learning.

Previous studies have proved that observational learning can induce placebo analgesia, but the factors that influence observationally induced placebo analgesia have not yet been extensively examined. The primary goal of this study was to investigate the effect of information about the role that the observed person (model) plays in the experiment on the magnitude of the observationally induced placebo effect. This study also examined the contribution of the observer's empathy, conformity and fear of pain to the placebo analgesia induced by observational learning. The effects induced in two experimental groups and one control group were compared. Participants in the experimental groups observed a model introduced as either another participant taking part in the study or a coworker of the experimenter. The model rated the intensity of pain induced by electrocutaneous stimuli preceded by color stimuli. One-half of all participants watched a model rating pain stimuli preceded by the color orange as higher than stimuli preceded by the color blue; for the other half, the ratings were the opposite. There was no observation in the control group. Subsequently, all participants received pain stimuli of the same intensity preceded by orange and blue stimuli and rated the intensity of the experienced pain. Placebo analgesia was found in both experimental groups. However, the way the observed model was introduced to participants did not affect the magnitude of placebo analgesia. Thus, the study showed that the role played by the model is not crucial for observationally induced placebo analgesia. The examined observer's individual characteristics did not predict the magnitude of placebo effect.

Memory of pain in adults: a protocol for systematic review and meta-analysis.

BACKGROUND: The way pain is remembered and reported can affect medical decisions taken by patients and health-care professionals. Memory of pain has been investigated extensively for the past few decades; however, the results of previous studies are highly variable, indicating that the recollection of pain can be accurate, overestimated or underestimated. It is therefore difficult to conclude how well pain is remembered. The aim of this systematic review and meta-analysis is to summarize research findings on memory of pain in healthy adults and patients suffering from acute and chronic pain. METHODS: The systematic review will be performed by searching for articles indexed in the following databases: PubMed, MEDLINE, PsycINFO, Web of Science, ScienceDirect, PsycARTICLES, Scopus and Academic Search Complete. Studies will be included if (1) they investigated healthy adults or patients with any acute or chronic pain condition and if (2) they assessed experienced pain (pain intensity and/or pain unpleasantness) and its recollection. No restrictions related to the date of publication and recall delay will be applied. Studies will be screened for eligibility and risk of bias by two independent assessors. The risk of bias will be assessed by a modified Downs and Black checklist. A narrative synthesis will be performed in the first stage; in the second stage, the results of studies with comparable designs will be pooled in meta-analytical syntheses. DISCUSSION: The question of whether pain is remembered accurately is crucial for valid pain diagnosis, effective treatment and prognosis. So far, a number of studies on memory of pain have been conducted; however, a definitive conclusion on whether memory of pain is accurate is still lacking. In this systematic review and meta-analysis, available data will be pooled together to further inform research and clinical practice. SYSTEMATIC REVIEW REGISTRATION: PROSPERO CRD42018093523.

Reward for Pain: Hyperalgesia and Allodynia Induced by Operant Conditioning: Systematic Review and Meta-Analysis.

Learning processes have been discussed in the context of pain chronicity for decades. Particularly, operant conditioning has been used to experimentally induce and modulate pain in healthy humans. In this systematic review and meta-analysis, research findings on pain facilitation (hyperalgesic effect) and pain elicitation (allodynic effect) are evaluated. The review was performed according to the PRISMA guideline and an a priori published protocol. Nine databases were searched for relevant publications: PubMed, Cochrane Register of Controlled Trials (CENTRAL), Web of Science, ScienceDirect, EBSCO, PsycINFO, MEDLINE, PsycARTICLES, and CINAHL. Studies were included if they investigated pain-free humans, exposed to an operant conditioning procedure of pain. Two independent assessors screened publications against eligibility criteria and assessed the risk of bias with the Cochrane risk of bias scale. A total of 3155 records were screened, of which 8 were included in the qualitative (401 participants) and 5 into the quantitative (110 participants) synthesis. Results showed that hyperalgesic (standardized mean difference = -0.80, 95% confidence interval = -1.33 to -0.27, P = .003) and allodynic effects (standardized mean difference = -1.27, 95% confidence interval = -2.46 to -0.08, P = .04) can be induced in healthy humans, indicating that pain can be shaped by contingencies of reinforcement. However, the uncertainty of the effect is relatively high, mostly owing to the small number of included studies, demand characteristics, and the risk of bias. This is especially relevant for studies on allodynic effects where the decrease in nociception should be more rigorously controlled. PERSPECTIVE: Operant conditioning can be a mechanism of pain chronicity. All experimental studies investigating this hypothesis have been identified and summarized. It has been demonstrated that allodynic and hyperalgesic effects can be induced by operant conditioning.

Pain rewarded: hyperalgesic and allodynic effect of operant conditioning in healthy humans-protocol for a systematic review and meta-analysis.

BACKGROUND: 'Pain rewarded' is a hypothesis wherein acute pain sufferers are exposed to reinforcers and punishers from their environment that shape their behaviour, i.e. pain responses. Such a point of view has been taken for granted by many clinicians and researchers although existing evidence has not yet been systematically summarized. This planned systematic review and meta-analysis is aiming to summarize the research findings on pain modulation (hyperalgesic effect) and pain elicitation (allodynic effect) resulting from operant conditioning procedures in healthy humans. METHODS: The systematic review will be performed by searching for articles indexed in PubMed database, Cochrane Register of Controlled Trials (CENTRAL), Web of Science™, ScienceDirect, EBSCO database, PsycINFO, MEDLINE, PsycARTICLES and CINAHL. Studies will be included if they investigate healthy humans, exposed to modulation or elicitation of a pain experience induced by operant conditioning. Studies will be screened for eligibility and risk of bias by two independent assessors. Narrative and meta-analytical syntheses are planned. DISCUSSION: Data will be pooled and analyzed qualitatively and quantitatively (if possible) in order to advance the understanding of pain mechanisms, especially the development of chronic pain. This systematic review will guide the planning of future experiments and research by summarizing important technical details of conditioning procedures in healthy humans. SYSTEMATIC REVIEW REGISTRATION: PROSPERO CRD42017051763.