PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “PLACEBOS”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 37 records · Page 2Linked to original sources
PubMed1998

The specific effects of prior opioid exposure on placebo analgesia and placebo respiratory depression.

Although in most of the cases the placebo response appears to be unpredictable, several factors have been considered in order to explain the placebo analgesic effect. For example, it is widely recognized, albeit with little empirical evidence, that placebo analgesia is more likely to occur after a successful analgesic therapy. On the basis of this assumption, we tested the placebo response in a population of patients who were treated with buprenorphine the day before for relieving postoperative pain. However, due to the high variability of opioid responsiveness, buprenorphine was effective in some patients and poorly effective in some others. Similarly, buprenorphine produced respiratory depression with a large variability, ranging from mild depression to no effect. We found that the placebo analgesic response depended on the buprenorphine analgesic effectiveness of the previous day. Analogously, we found that a placebo respiratory depressant response was more pronounced in those patients with a respiratory depressant response to buprenorphine on the day before, irrespective of the analgesic effectiveness. These specific effects suggest that (1) the placebo effect is experience-dependent; (2) the mechanisms underlying placebo analgesia and placebo respiratory depression are independent from each other and, by considering the role of endogenous opioids in placebo analgesia, might involve different subpopulations of opioid receptors.

Analgesia↗
PubMed1994

Does a placebo run-in or a placebo treatment cell affect the efficacy of antidepressant medications?

During the last decade, there has been an increasing use of a placebo run-in period prior to randomization to active treatments, or placebo in randomized controlled trials aimed at establishing acute phase antidepressant drug efficacy in patients with major depression. This procedure is thought to reduce response rates to placebo treatment after randomization, thereby increasing the drug-placebo difference. Metaanalyses of 101 studies reveal that a placebo run-in does not (1) lower the placebo response rate, (2) increase the drug-placebo difference, or (3) affect the drug response rate post-randomization in either inpatients or outpatients for any antidepressant drug group. If there is a post-randomization placebo treatment cell, drug response rates are unchanged or are slightly lower than if there is no placebo treatment cell for outpatients. These results suggest that a pill placebo run-in provides no advantage in acute phase efficacy trials.

Antidepressive Agents↗
PubMedDate not supplied

Placebo and placebo effect: their impact on the evaluation of drug response in patients.

Placebo, defined as any therapeutic procedure, without any specific activity, given deliberately to have an effect on a patient, symptom, syndrome or disease, has a great impact in the evaluation of drug response. The possible pathways via which the possible effect brings about clinical and physiological changes remain unknown, but a humoral mechanism seems to be implicated in some placebo effects (e.g. placebo-induced analgesia). The placebo effect depends on many factors, including the type of patient, the personality of the physician, the doctor-patient relationship and the type and even the colour of the drug preparation. Placebo control is important particularly when the disease is characterized by frequent spontaneous periods of acute exacerbation and remission. Functional (such as dyspepsia and irritable bowel syndrome) and organic (such as peptic ulcer and inflammatory bowel disease) gastrointestinal diseases have got great benefit from placebo-controlled clinical trials. In such trials the more effective the placebo is, the more difficult it will be to demonstrate the efficacy of active drug in statistical terms. Nevertheless, provided the use of placebo be ethical for a given condition, placebo-controlled trials are the only objective way of assessing correctly drug response in patients.

Drug Evaluation↗
PubMed1989

[Considerations of the placebo problem in acupuncture. Reflections on usefulness, ethical justification, standardization and differentiated use of placebos in acupuncture].

28 different acupuncture placebos were found in 28 controlled studies, making a comparison of the results impossible. The following differentiation of acupuncture placebos is proposed: 1.a) Real placebos without intrinsic effect, 1.b) Pseudoplacebos with intrinsic effect, 2.a) Placebos without damage of physical integrity (not incisive), 2.b) Placebos with damage of physical integrity (incisive), for example the usual method of placebo-acupuncture-needling outside the known acupuncture points with or without additional stimulation. Painful pseudoplacebos with damage of the physical integrity should only be used in short-term trials on experimentally induced pain in healthy volunteers. For therapeutic studies with really sick persons, only real placebos, painless and without damage of the physical integrity, should be used, e.g. mock-TENS or laser. In order to prevent the patient from knowing the group determination, a third group with another correct treatment is essential, e.g. correct acupuncture, mock-TENS and real TENS or laser. A genuine acupuncture placebo is as unthinkable as placebo-surgery. Since single- or double-blind trials cannot be correctly carried out in acupuncture therapy it appears desirable to replace them by follow-up studies.

Acupuncture Therapy↗
PubMed2003

Placebo effect and placebos: what are we talking about? Some conceptual and historical considerations.

Placebos and the placebo effect have always been present in medical history. However, they have not received the same consideration over the years. Somewhere between art and science, the placebo historical references come from Ancient Egypt and cross over the major civilisations, beliefs and scientific advances. The use of placebo as a methodological tool has assumed a leading role in the last 50 years and has become an important role in controlled clinical trials, the main element of the "evidence-based-medicine" paradigm. Knowledge of the conceptual and historical considerations of placebo may help to understand its role in medical practice. Even without a consensual definition, and assuming that the placebo effect does not seem to be fully dependent on a placebo administration, one issue seems unquestionable: the placebo effect is present in clinical practice and in clinical trials, no matter which name we choose to call it.

Clinical Trials as Topic↗
PubMed2002

[What is the effect of placebo interventions? A systematic review of randomized clinical trials with placebo treated and untreated patients].

INTRODUCTION: Placebo treatments have been reported to help patients with many diseases, but the quality of the evidence supporting this belief has not been rigorously evaluated. MATERIAL AND METHODS: We conducted a systematic review of clinical trials in which patients were randomised either to placebo treatment or to no treatment. A placebo intervention could be pharmacological (for instance, a tablet), physical (for instance manipulation), or psychological (for instance conversation). RESULTS: We identified 130 trials that met our inclusion criteria. After excluding 16, which gave no relevant outcome data, 32 with binary outcomes and 82 with continuous outcomes were left. As compared to no treatment, placebo had no significant effect on binary outcomes, the pooled relative risk was 0.95 (95% confidence interval 0.88 to 1.02), irrespective of whether these outcomes were subjective or objective. Placebo seemed to have a beneficial effect in the trials with continuous outcomes, the overall pooled standardised mean difference of the placebo and no-treatment groups was -0.28 (-0.38 to -0.19), but the effect decreased with increasing sample size, which indicates bias. The pooled standardised mean difference was significant for the trials with subjective outcomes, -0.36 (-0.47 to -0.25), but not for those with objective outcomes, -0.12 (-0.27 to 0.03). In trials involving the treatment of pain, placebo was reported to have a moderate beneficial effect, with a pooled standardised mean difference of -0.27 (-0.40 to -0.15), but bias, for instance reporting bias, was possible. CONCLUSION: We found no reliable evidence that placebo treatments in general had effects of clinical importance.

Evidence-Based Medicine↗
PubMed2002

Buprenorphine maintenance versus placebo or methadone maintenance for opioid dependence.

BACKGROUND: Buprenorphine has recently been reported to be an alternative to methadone and LAAM for maintenance treatment of opioid dependent individuals, differing results are reported concerning its relative effectiveness indicating the need for an integrative review. OBJECTIVES: To evaluate the effects of buprenorphine maintenance against placebo and methadone maintenance in retaining patients in treatment and in suppressing illicit drug use. SEARCH STRATEGY: We searched the following databases up to 2001, inclusive: Cochrane Drugs and Alcohol Review Group Register, the Cochrane Controlled Trials Register, MEDLINE, EMBASE, Current Contents, Psychlit, CORK [www. state.vt.su/adap/cork], Alcohol and Drug Council of Australia (ADCA) [www.adca.org.au], Australian Drug Foundation (ADF -VIC) [www.adf.org.au], Centre for Education and Information on Drugs and Alcohol (CEIDA) [www.ceida.net.au], Australian Bibliographic Network (ABN), and Library of Congress databases, available NIDA monographs and the College on Problems of Drug Dependence Inc. proceedings, the reference lists of all identified studies and published reviews and authors of identified RCT's were asked about any other published or unpublished relevant RCT. SELECTION CRITERIA: Randomised clinical trials of buprenorphine maintenance compared with either placebo or methadone maintenance for opioid dependence. DATA COLLECTION AND ANALYSIS: Reviewers evaluated the papers separately and independently, rating methodological quality of concealment of allocation; data were extracted independently for meta-analysis and double-entered. MAIN RESULTS: Thirteen studies met the inclusion criteria, all were randomised clinical trials, all but one were double-blind. The method of concealment of allocation was not clearly described in 11 of the studies, otherwise methodological quality was good. Buprenorphine given in flexible doses appeared statistically significantly less effective than methadone in retaining patient in treatment (RR= 0.82; 95% CI: 0.69-0.96). Low dose buprenorphine is not superior to low dose methadone. High dose buprenorphine does not retain more patients than low dose methadone, but may suppress heroin use better. There was no advantage for high dose buprenorphine over high dose methadone in retention (RR=0.79; 95% CI:0.62-1.01), and high dose buprenorphine was inferior in suppression of heroin use. Buprenorphine was statistically significantly superior to placebo medication in retention of patients in treatment at low doses (RR=1.24; 95% CI: 1.06-1.45), high doses (RR=1.21; 95% CI: 1.02-1.44), and very high doses (RR=1.52; 95% CI: 1.23-1.88). However, only high and very high dose buprenorphine suppressed heroin use significantly above placebo. REVIEWER'S CONCLUSIONS: Buprenorphine is an effective intervention for use in the maintenance treatment of heroin dependence, but it is not more effective than methadone at adequate dosages.

Buprenorphine↗
PubMed2001

Placebos, placebo effect, and the response to the healing situation: the evolution of a concept.

In spite of its impressive progress, medicine has been strongly criticized for relying on its modern biomedical tradition to the neglect of the psychosocial aspects of health. This neglect may account for patients' dissatisfaction and eventual use of alternative health approaches. The concept of placebo has sustained dramatic "protean" metamorphoses through the ages. For centuries, placebos have been regarded as powerful deceptive therapies. From the middle of the twentieth century, however, conventional medicine has used placebos as methodologic tools to distinguish the specific from the nonspecific ingredients in treatments. In modern medical research, the double-blind, placebo-controlled, randomized clinical trial has been established as the gold standard for the assessment of any new treatment. Recently a new trend regarding placebos seems to have emerged. The placebo and other nonspecific effects elicited by the "healing situation" have been independently subjected to scientific study. Progress in this area may promote useful clinical applications, enabling physicians to broaden their perspectives on the healing process. We present the historical changes of the concept of placebo and the ethical issues raised by their use.

Attitude to Health↗
PubMed2000

Chlorpromazine versus placebo for schizophrenia.

BACKGROUND: Chlorpromazine, formulated in the 1950s, remains a benchmark treatment for those with schizophrenia. OBJECTIVES: To evaluate the effects of chlorpromazine for schizophrenia in comparison to placebo. SEARCH STRATEGY: Electronic searches of Biological Abstracts (1982-1995), The Cochrane Library (1999, Issue 2), The Cochrane Schizophrenia Group's Register (October 1999), EMBASE (1980-1995), MEDLINE (1966-1995), PsycLIT (1974-1995) were undertaken. References of all identified studies were searched for further trial citations. Pharmaceutical companies and authors of trials were contacted. SELECTION CRITERIA: Randomised controlled trials relating to people with schizophrenia, and non-affective serious/chronic mental illness irrespective of mode of diagnosis evaluating chlorpromazine (any dose) versus placebo. Primary outcomes of interest were death, violent behaviours, overall improvement, relapse and satisfaction with care. DATA COLLECTION AND ANALYSIS: Citations and, where possible, abstracts were independently inspected by reviewers, papers ordered, re-inspected and quality assessed. Data were extracted by BT with CA and GA independently checking a 10% sample for reliability. Dichotomous data were analysed using random effects relative risk (RR) and the 95% confidence interval around this was estimated. Where possible the number needed to treat (NNT) or number needed to harm statistics (NNH) were calculated. Continuous data were excluded if more than 50% of people were lost to follow up, but, where possible, weighted mean difference was calculated. Sensitivity analyses have not been undertaken for this version of the review. MAIN RESULTS: Over 1000 electronic records were inspected. The review currently mentions 202 papers in its Excluded Studies section and 45 studies in its Included Studies table. Six papers await assessment. Chlorpromazine reduces relapse over six months to two years (RR 0.65 CI 0.5-0.9, NNT 3 CI 2.5-4) and there is convincing evidence from trials that it promotes a global improvement in a person's symptoms and functioning (RR 0.76 CI 0.7-0.9, NNT 7 CI 5-10) although the placebo response is also considerable (nearly 40%). Fewer people allocated to chlorpromazine leave trials early (RR 0.76 CI 0.6-1.1). There are many adverse effects. Chlorpromazine is clearly sedating (RR 2.4 CI 1.7-3.3, NNH 6 CI 4-8), it increases a person's chances of experiencing acute movement disorders (RR 3.1 CI 1.3-7.6, NNH 24 CI 14-77), parkinsonism (RR 2.6 CI 1.2-5.4, NNH 10 CI 8-16) and fits (RR 2.4 CI 0.4-16). Amongst other things it clearly causes a lowering of blood pressure with accompanying dizziness (RR 1.9 CI 1. 3-2.6, NNH 12 CI 8-22) and considerable increases in weight (RR 4.4 CI 2.1-9, NNH 3 CI 2-5). REVIEWER'S CONCLUSIONS: This review will confirm much that clinicians and recipients of care already know but provides quantification to support clinical impression. Despite the humbling 40% improvement rate in those who were allocated to placebo, chlorpromazine's global position as the 'benchmark' treatment of those with psychoses is not threatened by this review. Chlorpromazine, in common use for nearly half a century, is a well established but imperfect treatment. Judicious use of this best available evidence should lead to better informed decisions both by carers and those with psychotic illnesses.

Antipsychotic Agents↗
PubMed1997

A comparison of the effect of ramipril, felodipine and placebo on glomerular filtration rate, albuminuria, blood pressure and vasoactive hormones in chronic glomerulonephritis. A randomized, prospective, double-blind, placebo-controlled study over two years.

The effects of an ACE-inhibitor (ramipril), a calcium antagonist (felodipine) and placebo on glomerular filtration rate (GFR), urinary albumin/creatinine ratio, blood pressure (BP) and vasoactive hormones were investigated in a randomized, prospective, double-blind, placebo-controlled study of patients with chronic glomerulonephritis and hypertension, with measurements at entrance and after 12 and 24 months. In total, 33 patients were included: 21 completed the study with 7 patients in each group. GFR was measured as 51Cr-EDTA clearance and the vasoactive hormones with radioimmunoassays. The reduction in GFR was significantly more pronounced in the felodipine group (-7 ml/min) than in the ramipril group (0 ml/min) but the same as in the placebo group (-6 ml/min). The urinary albumin/creatinine ratio was significantly more reduced in the ramipril group (-74 mg/mmol) than in the placebo group (-11 mg/mmol), which did not deviate from the felodipine group (-10 mg/mmol). BP was significantly reduced by ramipril and felodipine, but not by placebo. Angiotensin II and aldosterone in plasma increased or tended to increase in the felodipine and placebo groups, but were unchanged in the ramipril group. Endothelin increased only in the placebo group, and vasopressin, atrial natriuretic peptide, and brain natriuretic peptide were not significantly changed in any of the groups. It is concluded that ramipril seems to be superior to felodipine in chronic glomerulonephritis owing to better preservation of GFR.

Adolescent↗
PubMed2001

Patients with severe depression may benefit from buspirone augmentation of selective serotonin reuptake inhibitors: results from a placebo-controlled, randomized, double-blind, placebo wash-in study.

BACKGROUND: Although case reports and open studies have reported augmentation with buspirone to be beneficial in the treatment of depression refractory to treatment with a selective serotonin reuptake inhibitor (SSRI), a recently published randomized, placebo-controlled, double-blind study failed to show superiority of buspirone over placebo in this respect. METHOD: One hundred two outpatients who fulfilled DSM-IV criteria for a major depressive episode and who had failed to respond to a minimum of 6 weeks of treatment with either fluoxetine or citalopram were included in this double-blind, randomized, placebo-controlled study. After a single-blind placebo wash-in period of 2 weeks while continuing their SSRI, the patients were randomly assigned to adjunctive treatment with either buspirone, 10 to 30 mg b.i.d., or placebo for 6 weeks. Patients were assessed using the Montgomery-Asberg Depression Rating Scale (MADRS), the Clinical Global Impressions scale (CGI), and visual analogue scales. RESULTS: After the first week of double-blind treatment, there was a significantly greater reduction in MADRS score (p = .034) in the buspirone group as compared with placebo. At endpoint, there was no significant difference between treatment groups as a whole, although patients with initially high MADRS scores (> 30) showed a significantly greater reduction in MADRS score (p = .026) in the buspirone group as compared with placebo. CONCLUSION: Patients with severe depressive symptoms may benefit from augmentation with buspirone. It cannot be excluded that augmentation with buspirone may speed up the antidepressive response of patients refractory to treatment with fluoxetine or citalopram.

Adult↗
PubMed2003

A double-blind, randomized, placebo-controlled trial of augmentation with lamotrigine or placebo in patients concomitantly treated with fluoxetine for resistant major depressive episodes.

BACKGROUND: Evidence of the antidepressant efficacy of lamotrigine is increasing, although there are no placebo-controlled trials of lamotrigine augmentation in depression. The aim of this study was to assess if augmentation with lamotrigine was superior to placebo in patients who were receiving fluoxetine for resistant major depressive episodes. METHOD: Twenty-three patients who had experienced at least 1 major depressive episode that was resistant to at least 1 prior trial of antidepressant therapy were selected. These patients were treated with fluoxetine, 20 mg/day, and concomitantly randomly assigned to receive either lamotrigine (N = 13) or placebo (N = 10) for 6 weeks. The dose of lamotrigine was titrated upward from 25 mg/day to 100 mg/day. Patients suffering from bipolar II disorder (N = 8) or from major depressive disorder (N = 15) (DSM-IV criteria) were enrolled, resulting in heterogeneity of the sample. The primary outcome measure was Hamilton Rating Scale for Depression score. Data were collected from 2000-2001. RESULTS: Lamotrigine was statistically superior to placebo on the Clinical Global Impressions scale at endpoint, both in absolute terms (mean +/- SD Clinical Global Impressions-Severity of Illness scores: lamotrigine, 2.15 +/- 1.28; placebo, 3.40 +/- 1.17; p =.0308) and using a responder analysis, with response defined as a Clinical Global Impressions-Improvement score of 2 or less (lamotrigine, 84.62% [N = 11]; placebo, 30.00% [N = 3]; p =.013). The effect of lamotrigine on Clinical Global Impressions scale scores was seen in both major depressive disorder and bipolar II disorder. Lamotrigine, however, failed to separate statistically from placebo on the Hamilton Rating Scale for Depression and Montgomery-Asberg Depression Rating Scale. This failure to differentiate on a primary outcome measure is essentially a negative study result. This result is most likely an artifact of the small sample size used and the resultant limited power of the study. CONCLUSION: The results of this trial add to the literature suggesting potential efficacy of the antidepressant profile of lamotrigine. In addition, this study points to a possible role of lamotrigine as an augmentation agent in depression.

Adolescent↗
PubMed1986

Responders, nonresponders, and placebo responders among children with attention deficit disorder. Importance of a blinded placebo evaluation.

The responses to methylphenidate of 118 children with attention deficit disorder (ADD) were studied under double-blind conditions. Three distinct types of response to medication and placebo were found, as determined by teacher ratings. One group, called "responders," improved dramatically in attention and hyperactivity ratings on active medication but showed essentially no change from baseline when on placebo. The group called "nonresponders" showed minimal change in ratings on either placebo or medication. The third group, "placebo responders," showed almost as much improvement as the responders on medication, but their ratings were not very different from medication ratings during the placebo trial. The placebo responders, 18 percent of the group, would have been considered responders in a nonplacebo-controlled study. Double-blind placebo evaluation of ADD children can and should be done by practitioners to avoid medicating children who are responding to nonspecific effects of drugs.

Analysis of Variance↗