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PubMed2001

The scientific and ethical basis for placebo-controlled trials in depression and schizophrenia: an FDA perspective.

There is a tension between the need for scientifically valid trials of new psychotropic drugs and concern about conducting placebo-controlled trials, the trials psychopharmacologists consider the gold standard trial, when this requires that some patients be denied existing effective therapy. This paper will review the scientific principles supporting the need for placebo-controlled trials in depression and schizophrenia, and will provide preliminary data on failure rates of placebo-controlled trials for these disorders, as illustrations of the application of these principles. Next, the ethical issues pertinent to the conduct of placebo-controlled trials for these two serious psychiatric disorders will be reviewed. Preliminary data on suicides in placebo-controlled depression and schizophrenia trials will be presented to argue for the ethical acceptability of the conduct of placebo-controlled trials in these two conditions.

Depressive Disorder↗
PubMed2001

Placebo affects the performance of rats in models of depression: is it a good control for behavioral experiments?

Experimental design of behavioral studies in animals generally includes placebo-treated controls. However, when placebo is administered by injection in experimental models of psychiatric diseases such as depression, where stress may affect the execution of the behavioral test, it is possible that injection per se may influence the behavioral response. Rats injected with clomipramine hydrochloride (1, 10 or 50 mg/kg), as compared to animals injected with physiological saline as placebo, showed a dose-dependent decrease of the immobility time in the despair test and of the number of floor units explored in the open field in the reserpine test. However, when animals injected with placebo or clomipramine 50 mg/kg were compared with untreated intact controls, it was found that the immobility time in the despair test was higher in the placebo-treated animals than in untreated intact controls. A difference was found between clomipramine-injected animals and untreated intact controls. In contrast, rats tested in the reserpine test, which is based on repeated drug injections, no difference was found between placebo-treated animals and untreated intact controls. These results indicate that stressful procedure of the experimental design may change the response of animals in behavioral tests. Studies with experimental models of depression, where stressful procedures are used, should include a control group of untreated intact animals.

Animals↗
PubMed1996

Prospective, randomized, double-blind, placebo-controlled comparison of metoclopramide and ondansetron for prevention of posttonsillectomy or adenotonsillectomy emesis.

STUDY OBJECTIVE: To compare the antimetic efficacy of prophylactic ondansetron, metoclopramide, and placebo for prevention of postoperative vomiting in pediatric tonsillectomy or adenotonsillectomy patients. DESIGN: Prospective, randomized, double-blind, placebo controlled study. SETTING: Children's hospital. PATIENTS: 132 ASA status I and II children, ages 2 to 12 years, undergoing tonsillectomy or adenotonsillectomy. INTERVENTIONS: Patients received intravenous (IV) melodopramide 0.25 mg/kg, IV on dansetron 0.15 mg/kg, or IV saline placebo after induction of standardized halothane, nitrous oxide, and oxygen anesthesia. Muscle relaxants and their antagonists were allowed. Patients received postoperative analgesics as needed. MEASUREMENTS AND MAIN RESULTS: Incidence of postoperative vomiting, time of vomitting onset, and hospital length of stay (LOS) were measured. Patients who were admitted were excluded from LOS analysis. The postoperative incidence of vomiting was 54% for patients receiving metoclopramide, 26% for patients receiving ondansetron, and 69% for the placebo group. These differences were significant for ondansetron versus metoclopramide (p = 0.008) and placebo (p = 0.001). The mean (SD) LOS was significantly shorter for patients not vomiting 488 (88) minutes for vomiters versus 435 (65) minutes for non-vomiters. CONCLUSIONS: Prophylactic ondansetron is more effective than metoclopramide or placebo for the prevention of vomiting after tonsillectomy or adenotonsillectomy. Patients who do not vomit postoperatively have shorter LOS.

Adenoidectomy↗
PubMed2002

Attitudes to the contribution of placebo in acupuncture--a survey.

Interest in placebo is increasing, and recent research suggests that the therapeutic consequence of placebo is generated through mental processes in which attitudes are important. The aim of this study is therefore to explore attitudes and beliefs concerning placebo effect in acupuncture therapy, among doctors, patients and acupuncturists. From February 1994 until June 1995, four anonymous questionnaires were distributed among 1135 randomly selected doctors, 294 medical students, 432 acupuncturists and a random sample of 653 in the general population in Norway. Fifty-seven percent indicated the treatment effect seen in acupuncture as mainly a genuine acupuncture effect, 30% indicated that half of the effect in acupuncture comes from placebo, while 13% indicated that the treatment effect in acupuncture is mainly based on placebo. Doctors and students express a more skeptical view than the others, and having tried acupuncture for one's own disease is significantly associated with a less skeptical view within all study groups. Attitudes to the use of acupuncture for cancer patients are associated with attitudes to placebo for doctors and medical students, but not for the general population or acupuncturists.

Acupuncture Therapy↗
PubMed2001

Recombinant tissue plasminogen activator (alteplase) for restoration of flow in occluded central venous access devices: a double-blind placebo-controlled trial--the Cardiovascular Thrombolytic to Open Occluded Lines (COOL) efficacy trial.

PURPOSE: Central venous access devices (CVADs) are a mainstay of current medical therapy but often become occluded by thrombus. Tissue plasminogen activator (alteplase), at a dose of 2 mg per 2 mL, has been shown to be effective in restoring flow to catheters proven by radiographic contrast injection to be occluded by thrombus. The purpose of this double-blind placebo-controlled multicenter trial was to determine the efficacy of alteplase in occluded catheters without earlier contrast injections or radiographic examinations. MATERIALS AND METHODS: Patients were eligible for inclusion if blood could not be withdrawn from their catheter after a period of normal function of at least 48 hours. Single or multiple catheters, peripherally inserted central catheters, catheters with valves, and implanted ports were eligible; catheters used for hemodialysis were not included. Patients were randomly assigned to one of two groups. In one group, patients received a first dose of 2 mg alteplase followed, if needed, by a second dose of 2 mg alteplase and a third dose of placebo. The other group received placebo first followed by one 2-mg dose of alteplase and then a second, if needed. Each dose was allowed to dwell for 2 hours and ability to withdraw blood from the catheter was reassessed. The endpoint was restoration of the ability to withdraw and infuse through the catheter. One hundred forty-nine patients were randomized: 74 received placebo first, 75 received alteplase first. RESULTS: After the first 2-hour treatment, function was restored to 74% in the alteplase arm and 17% in the placebo arm (P <.0001 compared to placebo). After one or two treatments, function was restored in 90% of patients. There were no serious study-drug-related adverse events, no intracranial hemorrhage, no major hemorrhage, and no embolic events. CONCLUSION: Infusion of alteplase appeared to be safe and effective in restoring flow to occluded catheters without need for pretreatment radiographic evaluation.

Catheterization, Central Venous↗
PubMed2006

Effects of rupatadine vs placebo on allergen-induced symptoms in patients exposed to aeroallergens in the Vienna Challenge Chamber.

BACKGROUND: Rupatadine is a novel compound with potent dual antihistamine and platelet-activating factor antagonist activities and no sedative effects. OBJECTIVE: To evaluate the efficacy of rupatadine, 10 mg once daily, and placebo on allergen-induced symptoms (including nasal congestion), nasal airflow, nasal secretion, and subjective tolerability in response to grass pollen in a controlled allergen-exposure chamber. METHODS: In a randomized, double-blind, placebo-controlled, crossover trial, 45 patients with a history of seasonal allergic rhinitis received rupatadine or placebo every morning for 8 days in 2 different periods separated by a 14-day washout interval. On day 8 of each crossover period, patients underwent a 6-hour allergen exposure in the Vienna Challenge Chamber, where a constant and homogeneous concentration of aeroallergens was maintained. Subjective and objective assessments were performed online during the exposure. RESULTS: Subjective single and composite nasal and nonnasal symptoms were consistently less severe with rupatadine use than with placebo use starting from the first evaluation at 15 minutes to the end of the 6-hour Vienna Challenge Chamber challenge, with the most significant effects seen for nasal rhinorrhea, nasal itching, sneezing attacks, and total nasal symptoms (P < .001 for all). All the other symptoms (including nasal congestion, P < or = .005) were also significantly reduced with active treatment compared with placebo use. Mean secretion weights and overall feeling of complaint were significantly lower with rupatadine therapy than with placebo use (P < or = .001). Overall, rupatadine treatment was well tolerated. CONCLUSION: Rupatadine treatment is effective and well tolerated in patients with allergen-induced symptoms exposed to aeroallergens in a controlled exposure chamber.

Adolescent↗
PubMed2003

Recent placebo-controlled acute trials in bipolar depression: focus on methodology.

The completion of three recent large-scale, double-blind controlled acute trials in bipolar I depression has improved our understanding of the management of major depressive episodes associated with bipolar disorder. In contrast to the cross-over designs used in the early studies of lithium in bipolar depression, the designs utilized in these recent studies have employed random assignment to parallel arms including the use of placebo as a monotherapy in one study. The analyses of recent studies have all been conducted on intent-to-treat data, and included two types, change from baseline analyses and responder analyses. Lamotrigine monotherapy was shown to be superior to placebo with both types of analyses on the Montgomery-Asberg Depression Rating Scale (MADRS) and the Clinical Global Impressions (CGI) scales, but not the 17-item Hamilton Depression Rating Scale (HAMD) (n=195). The percentage of patients responding to placebo as a monotherapy were 29, 26 and 37%, respectively; there were no differences in switch rates (5% vs. 5%). Paroxetine augmentation was no better than placebo augmentation overall with both types analyses on the CGI and HAMD (n=117); the MADRS was not used. In patients with lithium levels < or =0.8 mequiv./l, the change from baseline analysis showed paroxetine to be superior to placebo, but responder analyses were negative; switch rates with paroxetine, imipramine, and placebo were 0, 8 and 2%. Moclobemide monotherapy was similar in efficacy to imipramine (n=156), but had a lower rate of switching (4% vs. 11%).

Antidepressive Agents↗
PubMed2003

Clinical effects of a new mouthrinse containing chlorhexidine, cetylpyridinium chloride and zinc-lactate on oral halitosis. A dual-center, double-blind placebo-controlled study.

OBJECTIVES: The aim of this double-blind, parallel study was to test the clinical efficacy of a newly developed mouthrinse in the treatment of oral halitosis in patients without periodontitis. MATERIAL AND METHODS: Forty volunteers, recruited in two centers, participated in this study. Patients were selected on the basis of (1) halitosis of oral origin, (2) full-mouth organoleptic score>1, using an arbitrary 0-5 scale, (3) level of volatile sulfur compounds (VSC)>170 parts per billion (ppb) and (4) Winkel tongue coating index (WTCI)>4 (0-12). Intervention included gargling with a mouthrinse containing chlorhexidine (0.05%), cetylpyridinium chloride (0.05%) and zinc-lactate (0.14%) or with a placebo mouthrinse without active ingredients. At days 0 and 14 clinical variables were assessed in order of performance: (1) organoleptic assessments, (2) levels of VSC, and (3) WTCI. RESULTS: Treatment with the active mouthrinse resulted in a significant mean reduction in the organoleptic score from 2.8 to 1.5 (p<0.005). In the placebo group, no significant reduction in the mean organoleptic score occurred. Consequently, this resulted, after 2 weeks, in a greater change of the organoleptic scores in the test group in comparison to the placebo group (p<0.005). The mean VSC scores were reduced from 292 to 172 ppb in the test group (p<0.005), whereas no reduction was observed in the placebo group. At the 2-week examination, the mean change of the VSC scores in the test group was significantly greater than the mean change in the placebo group (p<0.005). Neither in the test nor in the placebo group a significant reduction in tongue coating was observed. CONCLUSIONS: In conclusion, the tested mouthrinse is effective in the treatment of oral halitosis.

Adult↗
PubMed1996

The magical number .7 +/- .2: meta-meta-analysis of the probability of superior outcome in comparisons involving therapy, placebo, and control.

The "probability of superiority estimate" (PS) estimates the probability that a randomly sampled client from a population given a treatment will have an outcome that is superior to that of a randomly sampled client from a population given another treatment. The meta-analytic clinical outcome literature was examined to calculate mean PS (PS) for comparisons involving therapy versus control, therapy versus placebo, therapy versus therapy, and placebo versus control. The range of PS was found to be approximately .7 +/- .2, with median PS greatest when therapy and control are compared (Mdn PSTC = .70, where T = therapy and C = control) and least when 2 therapies are compared (Mdn PSTT = .56). Results suggested that there is more to therapeutic success than placebo effects (Mdn PSTP = .66, where T = therapy and P = placebo) and that placebo is typically better than do-nothing control conditions (Mdn PSPC = .62). The present exceptionally large study, controlling for dependencies and confounding variables, may put to rest the question of the superiority of therapy to placebo. It also appears that the strength of effect of therapy is typically at least average among the effects of independent variables in psychology.

Adult↗
PubMed2003

Establishing specificity in psychotherapy: a meta-analysis of structural equivalence of placebo controls.

Placebo treatments in psychotherapy cannot adequately control for all common factors, which thereby attenuates their effects vis-a-vis active treatments. In this study, the authors used meta-analytic procedures to test one possible factor contributing to the attenuation of effects: structural inequalities between placebo and active treatments. Structural aspects of the placebo included number and duration of sessions, training of therapist, format of therapy, and restriction of topics. Results indicate that comparisons between active treatments and structurally inequivalent placebos produced larger effects than comparisons between active treatments and structurally equivalent placebos: moreover, the latter comparison produced negligible effects, indicating that active treatments were not demonstrably superior to well-designed placebos.

Adult↗
PubMed2004

The placebo effect: dissolving the expectancy versus conditioning debate.

The authors review the literature on the 2 main models of the placebo effect: expectancy theory and classical conditioning. A path is suggested to dissolving the theoretical impasse that has long plagued this issue. The key is to make a clear distinction between 2 questions: What factors shape placebo effects? and What learning mediates the placebo effect? The reviewed literature suggests that classical conditioning procedures are one shaping factor but that verbal information can also shape placebo effects. The literature also suggests that conditioning procedures and other sources of information sometimes shape conscious expectancies and that these expectancies mediate some placebo effects; however, in other cases conditioning procedures appear to shape placebo effects that are not mediated by conscious cognition.

Cognition↗
PubMed2004

The placebo puzzle: putting together the pieces.

This article outlines and assesses the main theories of the placebo effect and suggests how they might sit together in a larger model of placebo etiology. Among the approaches considered are expectancy theory, emotional change theory, classical conditioning, and the biological approach. Although these are sometimes assumed to be competing models, in many cases they shed light on different pans of the placebo puzzle. Expectancies are the core of most placebo effects in human beings. The effects of expectancies are sometimes unmediated but in other cases are mediated by changes in emotional state, immune system function, perception, or behavior. Although expectancies are implicated in most placebo effects, a small number of placebo effects may be solely attributable to nonconscious contingency learning.

Affect↗
PubMed1989

Comparison of intravenous dilevalol with placebo in moderate hypertension.

Dilevalol, an agent that combines nonselective beta-blocking and beta 2-mediated vasodilating properties, was compared with placebo in 16 subjects with moderate hypertension in a double-blind crossover study. Dilevalol or a placebo was administered intravenously in bolus injections of 25, 50, and 50 mg at 15-minute intervals. Fifteen minutes after a cumulative dose of 125 mg, the blood pressure was lowered by 11/9 mm Hg, compared with 2/1 mm Hg after placebo (p less than 0.01 between groups for systolic and diastolic blood pressure), an effect that persisted for at least 105 minutes. Standing systolic blood pressure was also lowered in dilevalol-treated patients without orthostatic symptoms. No significant effects on heart rate were noted. Fifteen minutes after the last dose of dilevalol, plasma norepinephrine levels increased from a baseline of 200 +/- 24 to 495 +/- 44 pg/ml (p less than 0.01), compared with a nonsignificant rise from 262 +/- 21 to 306 +/- 28 pg/ml with placebo vehicle. Dilevalol also increased alpha-human atrial natriuretic factor by 5.4 pg/ml, compared with 0.5 pg/ml after placebo (p less than 0.01 between groups). Plasma renin activity and plasma epinephrine, aldosterone, and cyclic guanosine monophosphate levels were unchanged by dilevalol. There were no significant adverse effects with dilevalol administration. Compared with placebo, dilevalol given intravenously appears to be safe and effective antihypertensive treatment.

Aldosterone↗
PubMed2000

Six-month treatment of obesity with sibutramine 15 mg; a double-blind, placebo-controlled monocenter clinical trial in a Hispanic population.

OBJECTIVE: To evaluate the safety and efficacy of sibutramine 15 mg by mouth once per day in obese patients over a period of 6 months. RESEARCH METHODS AND PROCEDURES: A monocenter, double-blind, placebo controlled, parallel, prospective clinical trial was carried out. Sixty-nine male and female obese patients (body mass index [BMI] > 30 kg/m2) aged 16 to 65 years entered the trial. RESULTS: 22 of 35 patients in the sibutramine group and 9 of 34 patients in the placebo group completed the trial. The high dropout rate in the sibutramine group was due to adverse events in 3 cases, lack of efficacy (as judged by patients) in 7, loss to follow-up in 2, and an orthopedic device being worn in 1; in the placebo group the dropouts were ascribed to lack of efficacy (as judged by patients) in 17 cases and to loss to follow-up in 8 cases. Using the method of last observation carried forward, the weight loss in the sibutramine group was 10.27 kg (95% confidence intervals [95% CI] 7.66; 13.07) and 1.26 kg (95% CI 0.3; 2.23) in the placebo group. The BMI loss was 4.17 kg/m2 (95% CI 3.11; 5.22) in the sibutramine group and 0.53 kg/m2 (95% CI 0.13; 0.92) in the placebo group. The waist circumference reduction was 12.51 cm (95% CI 9.25; 15.77) in the sibutramine group and 3.26 cm (95% CI 1.38; 5.14) in the control group (p<0.05 by paired Student's t test for all the intragroup comparisons). Twenty-three sibutramine patients had 34 adverse events, the most frequent adverse events in the sibutramine group were upper respiratory tract infections (n = 6) and constipation (n = 6); 16 placebo patients had 21 adverse events. Three sibutramine patients withdrew their informed consent when they had adverse events. DISCUSSION: The results show that sibutramine induces significant loss of body weight and waist circumference. Cardiovascular function was not significantly affected by sibutramine. Sibutramine was well tolerated by most of the patients.

Adolescent↗
PubMed2003

A 6-month randomized, placebo-controlled, dose-ranging trial of topiramate for weight loss in obesity.

OBJECTIVE: To evaluate the efficacy and safety of topiramate (TPM) for weight loss in healthy obese subjects. RESEARCH METHODS AND PROCEDURES: A randomized, double-blind, placebo-controlled, dose-ranging trial was conducted. Three hundred eighty-five subjects, 18 and 75 years of age, were randomized to receive either placebo or TPM at 64, 96, 192, or 384 mg daily. Dosing began at 16 mg once daily. In week 2, the dose was increased to 16 mg twice daily. Thereafter, the dose was raised every week by 32 mg/d (16 mg twice daily) until subjects reached their target dose. Twenty-four weeks after beginning treatment, all subjects were tapered off treatment by a dose reduction of 50% per week. All participants received the same lifestyle program. RESULTS: Mean percent weight loss from baseline to week 24 was -2.6% in placebo-treated patients vs. -5.0%, -4.8%, -6.3%, and -6.3% in the 64, 96, 192, and 384 mg/d TPM groups, respectively. Greater percentages of TPM-treated patients lost at least 5% or 10% of body weight compared with placebo. The most frequent adverse events were related to the central or peripheral nervous system, including paresthesia, somnolence, and difficulty with memory, concentration, and attention. Most events were dose-related, occurred early in treatment, and usually resolved spontaneously; only 21% receiving TPM withdrew due to adverse events compared with 11% on placebo. DISCUSSION: TPM produced significantly greater weight loss than placebo at all doses.

Adolescent↗
PubMed2000

Roquinimex (Linomide) vs placebo in AML after autologous bone marrow transplantation.

Roquinimex, Linomide, a quinoline derivative with pleiotropic immunomodulatory activity, has previously been shown to enhance natural killer (NK) cell number and activity after ABMT in patients with AML. In this study 278 AML patients in remission were randomized to receive Roquinimex 0.2 mg/kg body weight or placebo twice weekly for 2 years following ABMT. Out of 139 patients in each group, 109 Roquinimex patients and 108 placebo patients were in their first CR. Median age at inclusion was 41 years for Roquinimex patients and 39 years for placebo patients. Twelve patients in each group had their marrow purged prior to reinfusion. Relapse and death were study endpoints. Surviving patients were followed for 2.6 to 6. 9 years. The total number of relapses was 60 in the Roquinimex group and 63 in the placebo group (not significant). Leukemia-free and overall survivals were similar in the two groups. Recovery of platelet counts was significantly delayed in the Roquinimex group as compared to placebo. No other significant differences regarding toxicity parameters were recorded. In conclusion, previous findings on NK cells could not be confirmed and the study showed no benefit for Roquinimex over placebo regarding relapse or survival following ABMT for AML in remission.

Adolescent↗
PubMed2006

Safety and efficacy of tamsulosin in the treatment of painful ejaculation: a randomized, double-blind, placebo-controlled study.

We evaluate the efficacy and safety of tamsulosin a selective alpha(1A)-receptor antagonist in patients with painful ejaculation (PE) as a sole entity. A total of 118 men with PE were included in the study. Patients were randomly assigned to receive 0.4 mg oral daily tamsulosin (group 1, n=59) or placebo (group 2, n=59), during a 6-week period for each agent. Pretreatment evaluation included history and physical examination, International Index of Erectile Function (IIEF) and a visual analog scale (VAS) for pain. The efficacy of two treatments was assessed every 2 weeks during treatment, and at the end of the study using responses to IIEF, VAS evaluation, mean intercourse satisfaction domain, mean weekly coitus episodes and adverse drug effects. In all, 104 patients (88%) completed the whole treatment schedule. Pain resolved in 16 and 13% of the patients treated with tamsulosin and placebo, respectively (P=0.1). Baseline mean intercourse satisfaction domain values of IIEF 10 and 11 reached to 12 and 10 at 6-week treatment in groups 1 and 2, respectively (P=0.08). The VAS after tamsulosin and placebo decreased from 5.7 and 5.8 to 5.1 and 5.5, respectively (P=0.1). The mean weekly intercourse episodes increased from pretreatment values of 1.8 and 1.6 to 1.9 and 1.7, for tamsulosin and placebo, respectively (P=0.08). Mean number of adverse events was 11 for tamsulosin and 5 for placebo (P<0.05). Tamsulosin is no better than placebo in improvement of PE as a sole entity.

Adult↗
PubMed1999

Inducing placebo respiratory depressant responses in humans via opioid receptors.

Several lines of evidence indicate that placebos produce analgesia through the activation of endogenous opioid systems. Recently, we showed that placebos may also produce respiratory depressant responses, a typical side-effect of narcotics, when a subject had a prior experience of respiratory depression in the course of narcotic treatment. In the present study, we report that the placebo respiratory depression can be induced after repeated administrations of the partial opioid agonist buprenorphine. The placebo respiratory depressant effect that resulted from the buprenorphine conditioning was completely blocked by a dose of 10 mg of naloxone, indicating that it was mediated by endogenous opioids. These findings show that placebos act, via the activation of opioid receptors, not only on pain mechanisms but on the respiratory centres as well, thus mimicking a typical side-effect of narcotics. In addition, the experimental procedure we used did not produce any expectation of respiratory depression and, similarly, the subjects did not notice any sign of respiratory discomfort. Thus, the placebo respiratory depression elicited in the present study cannot be explained on the basis of cognitive or motivational mechanisms. Rather, it appears to be a sequence effect due to learning, thus suggesting a conditioning mechanism mediated by endogenous opioids.

Aged↗