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PubMed2006

Effects of intensity of electroacupuncture upon experimental pain in healthy human volunteers: a randomized, double-blind, placebo-controlled study.

Electroacupuncture is commonly used for pain relief. Despite an extensive evidence-base guiding the selection of stimulation parameters, little methodologically robust research exists regarding the level of intensity required to provide effective doses. This study investigated the hypoalgesic effects of two stimulation intensities compared to placebo on pressure pain thresholds (PPTs) in pain-free humans. Forty-eight acupuncture-naïve volunteers (mean age 23), stratified by gender, were screened for relevant contraindications and randomly allocated to four groups: control, placebo, high-intensity ("to tolerance but sub-noxious") or low-intensity ("strong but comfortable"). True or placebo electroacupuncture, using the Streitberger placebo needle, was administered to acupoints on dominant forearm (LI10, TH5) and ipsilateral leg (GB34, ST38). True needles (30 mm long, 0.3 mm diameter) were inserted 20-25 mm and "de-qi" was elicited from active groups, prior to administering 30 min of 4 Hz, 200 micros electroacupuncture. No electrical stimulation was performed on control and placebo groups, and placebo needles were used. After the intervention period, all needles were removed. Volunteers were monitored for 30 further minutes. Two PPT measurements were taken bilaterally from muscle bellies of first dorsal interosseous by an independent rater, at baseline and at six subsequent 10-min intervals. Square-root transformed data were analysed using repeated-measures ANOVA, with baseline data as covariate. The high-intensity group was significantly different from the placebo group for both measurement sites (p=.020, p=.033). The control group displayed stable PPT readings over time. No significant differences were observed between the placebo and control groups. These findings suggest that high-intensity levels may be important in optimal dose selection.

Adolescent↗
PubMed2000

A multicenter, placebo-controlled pilot study of intravenous immune globulin treatment of antiphospholipid syndrome during pregnancy. The Pregnancy Loss Study Group.

OBJECTIVE: Treatment with heparin and low-dose aspirin improves fetal survival among women with antiphospholipid syndrome. Despite treatment, however, these pregnancies are frequently complicated by preeclampsia, fetal growth restriction, and placental insufficiency, often with the result of preterm birth. Small case series suggest that intravenous immune globulin may reduce the rates of these obstetric complications, but the efficacy of this treatment remains unproven. This pilot study was undertaken to determine the feasibility of a multicenter trial of intravenous immune globulin and to assess the impact on obstetric and neonatal outcomes among women with antiphospholipid syndrome of the addition of intravenous immune globulin to a heparin and low-dose aspirin regimen. STUDY DESIGN: This multicenter, randomized, double-blind pilot study compared treatment with heparin and low-dose aspirin plus intravenous immune globulin with heparin and low-dose aspirin plus placebo in a group of women who met strict criteria for antiphospholipid syndrome. All patients had lupus anticoagulant, medium to high levels of immunoglobulin G anticardiolipin antibodies, or both. Patients with a single live intrauterine fetus at </=12 weeks' gestation were randomly assigned to receive either intravenous immune globulin (1 g/kg body weight) or an identical-appearing placebo for 2 consecutive days each month until 36 weeks' gestation in addition to a heparin and low-dose aspirin regimen. Maternal characteristics, obstetric complications, and neonatal outcomes were compared with the Student t test and the Fisher exact test as appropriate. RESULTS: Sixteen women were enrolled during a 2-year period; 7 received intravenous immune globulin and 9 were given placebo. The groups were similar with respect to age, gravidity, number of previous pregnancy losses, and gestational age at the initiation of treatment. Obstetric outcomes were excellent in both groups, with all women being delivered of live-born infants after 32 weeks' gestation. The rates of antepartum complications such as preeclampsia, fetal growth restriction, and placental insufficiency (as manifested by fetal growth restriction or fetal distress) were similar between the 2 groups. Gestational age at delivery (intravenous immune globulin group, 34.6 +/- 1.1 weeks; placebo group, 36.7 +/- 2.1 weeks) and birth weights (intravenous immune globulin group, 2249.7 +/- 186.1 g; placebo group; 2604.4 +/- 868.9 g) were similar between the 2 groups. There were fewer cases of fetal growth restriction (intravenous immune globulin group, 0%; placebo group, 33%) and neonatal intensive care unit admission (intravenous immune globulin group, 20%; placebo group, 44%) among the infants in the intravenous immune globulin group than those in the placebo group, but these differences were not significant. CONCLUSION: A multicenter treatment trial of intravenous immune globulin is feasible. In this pilot study intravenous immune globulin did not improve obstetric or neonatal outcomes beyond those achieved with a heparin and low-dose aspirin regimen. Although not statistically significant, the findings of fewer cases of fetal growth restriction and neonatal intensive care unit admissions among the intravenous immune globulin-treated pregnancies may warrant expansion of the study.

Adult↗
PubMed2001

No gender differences in placebo responses of patients with major depressive disorder.

BACKGROUND: This study was designed to compare placebo responses in men and women. METHODS: Data for 501 women and 375 men with major depressive disorder treated with placebo from seven investigational randomized double-blind trials comparing fluoxetine with placebo were analyzed. Changes in major depressive disorder symptoms with placebo administration were measured as changes in total Hamilton Depression Rating Scale scores and adverse (nocebo) effects were measured by comparing treatment-emergent signs and symptoms. RESULTS: Both women and men with major depressive disorder showed significant symptomatic improvement following placebo administration, similar in magnitude and time course of response. Women on placebo reported slightly more nocebo effects than men. CONCLUSIONS: The finding that women and men with major depressive disorder demonstrated a similar therapeutic outcome after placebo administration suggests that gender is not a predictor of placebo response.

Adult↗
PubMed1997

Use of nafarelin versus placebo after reductive laparoscopic surgery for endometriosis.

OBJECTIVE: To evaluate the efficacy of the GnRH agonist (GnRH-a) nafarelin compared with placebo administered for 6 months after reductive laparoscopic surgery for symptomatic endometriosis. DESIGN: Randomized, prospective, placebo-controlled, multicenter clinical trial. SETTING: Thirteen clinics including private practice and university centers. PATIENT(S): One hundred nine women aged 18-47 with laparoscopically proven endometriosis and pelvic pain who had undergone reductive laparoscopic surgery for endometriosis. INTERVENTION(S): Patients were randomized to receive either the GnRH-a nafarelin (200 micrograms twice daily) or placebo for 6 months. MAIN OUTCOME MEASURE(S): Time to initiation of alternative treatment (the length of time from beginning study medication to receiving alternative therapy or to deeming that the study drug was ineffective) and patient-reported and physician-assessed pelvic pain scores. RESULT(S): The median time to initiation of alternative treatment was > 24 months in the nafarelin group versus 11.7 months in the placebo group. Fifteen (31%) of 49 nafarelin-treated patients required alternative therapy, compared with 25 (57%) of 44 placebo-treated patients. The patients' pelvic pain scores dropped significantly in the nafarelin and placebo groups after 6 months of treatment. Physician summary ratings showed significant improvement in the nafarelin group and no significant changes in the placebo group after 6 months of treatment. CONCLUSION(S): Compared with placebo, nafarelin administered after reductive laparoscopic surgery for endometriosis significantly delays the return of endometriosis symptoms requiring further treatment.

Adolescent↗
PubMed1998

Long-term effects of finasteride in patients with benign prostatic hyperplasia: a double-blind, placebo-controlled, multicenter study. PROWESS Study Group.

OBJECTIVES: To compare the long-term effects of finasteride (5 mg/day) and placebo in patients with moderate symptoms of benign prostatic hyperplasia (BPH). METHODS: Patients aged 50 to 75 years, with at least two urinary symptoms indicating moderate BPH, and an enlarged prostate, were followed in a 2-year double-blind, randomized, placebo-controlled multicenter study. The effects of finasteride versus placebo were assessed by total symptom score (modified Boyarsky), obstructive symptom score, maximal urinary flow rate, prostate volume, and urologic end points (acute urinary retention, BPH-related surgical intervention). RESULTS: Of the 3270 men enrolled, 3168 contributed data to the safety analysis, and 2902 to the efficacy evaluation. Significantly greater improvement with finasteride compared to placebo was observed at 12 and 24 months for total symptom score (mean -2.9 versus -1.9 at 12 months, P < or =0.001; -3.2 versus -1.5 at 24 months, P < or =0.001), obstructive symptom score (mean -1.9 versus -1.3 at 12 months, P < or =0.001; -2.1 versus -1.1 at 24 months, P < or =0.001), maximal urinary flow rate (mean +1.2 versus +0.6 mL/s at 12 months, P = 0.010; +1.5 versus +0.7 mL/s at 24 months, P = 0.002), and prostate volume (mean -14.2 versus +5.4% at 12 months, P < or =0.01; -15.3 versus +8.9% at 24 months, P < or =0.001). Greater improvements in placebo-adjusted total symptom score occurred in men with large prostates than in men with small prostates (mean -2.4 versus -1.1 at 12 months; -3.2 versus -1.3 at 24 months, placebo-adjusted data, P = 0.053). Fifteen of 1450 men (1.0%) in the finasteride group experienced an acute urinary retention event, compared with 37 of 1452 (2.5%) in the placebo group, and the corresponding figures for surgery were 51 of 1450 (3.5%) and 86 of 1452 (5.9%), respectively. The hazard rate for occurrence, computed using the log-rank statistic, decreased by 57% for acute urinary retention and by 40% for surgery accompanied by finasteride therapy compared to placebo. CONCLUSIONS: Finasteride causes long-term symptomatic improvement and reduces the risk of acute urinary retention or surgery. Men with enlarged prostates benefit most from finasteride treatment.

5-alpha Reductase Inhibitors↗
PubMed1978

The mechanism of placebo analgesia.

The effect of naloxone on dental postoperative pain was studied to examine the hypothesis that endorphins mediate placebo analgesia. All patients had extraction of impacted mandibular third molars with diazepam, N2O, and local block with mepivacaine. 3 h and 4 h after surgery naloxone or a placebo was given under randomised, double-blind conditions. Pain was evaluated on a visual analogue scale. Patients given naloxone reported significantly greater pain than those given placebo. Patients given placebo as their first drug was either placebo responders, whose pain was reduced or unchanged, or nonresponders whose pain increased. Naloxone given as a second drug produced no additional increase in pain levels in nonresponders but did increase pain levels of placebo responders. Nonresponders had a final mean pain rating identical to that of responders who received naloxone as their second drug. Thus the enhancement of reported pain produced by naloxone can be entirely accounted for by its effect on placebo responders. These data are consistent with the hypothesis that endorphin release mediates placebo analgesia for dental postoperative pain.

Adolescent↗
PubMed1997

Efficacy and safety of 0.3% carbomer gel compared to placebo in patients with moderate-to-severe dry eye syndrome.

PURPOSE: Carbomer gel is a water-soluble polymeric resin that has been reported to maintain the tear film in contact with the eye for an extended period. The efficacy and safety of this new artificial tear were assessed. METHODS: A multicenter, single-masked, randomized, placebo-controlled study was carried out on 123 patients with moderate-to-severe dry eyes. The placebo was a mannitol solution with benzalkonium chloride 0.008% as preservative. Patients were observed over an 8-week period, and subjective and objective changes analyzed, compared to a baseline of no therapy, after 1 to 7 days washout period from previous medication. RESULTS: All primary subjective symptoms decreased significantly in the carbomer gel-treated group compared to the placebo group (i.e., dryness, discomfort, and foreign body sensation). The carbomer gel also significantly improved the rose bengal staining score relative to placebo. When data for the primary subjective efficacy variables were stratified for disease severity, there was a statistically significant improvement from baseline by day 10 for severely affected patients and from day 42 for patients with moderate disease. Secondary subjective symptoms that improved significantly in the tear gel group compared to placebo were photophobia, erythema, tear breakup time, blurry-filmy, dry-sandy sensation, and physician impression. However, no significant improvements in the secondary subjective symptoms of tearing, itching, scaling, conjuctival discharge, palpebral conjunctival redness, bulbar conjuctival redness, conjunctival luster, relief of discomfort, ease of use, and overall acceptability were found in either group over the baseline score. In addition, neither carbomer gel nor placebo improved the baseline fluorescein staining score or the Schirmer test score. Two patients suffered local allergic reactions to the carbomer gel or its preservative, which settled on withdrawal of the medication. CONCLUSIONS: Carbomer gel was more efficacious than was placebo in improving a number of subjective and objective symptoms of moderate-to-severe dry eye syndrome. The results of this study indicate that carbomer gel was a safe as was the placebo.

Acrylic Resins↗
PubMed2003

Placebo-controlled trials do not find association of olanzapine with exacerbation of bipolar mania.

BACKGROUND: Published case reports describe apparent induction or exacerbation of manic-like symptoms during treatment with the atypical antipsychotics olanzapine and risperidone. To date, such reports are from uncontrolled clinical experience and therefore cannot clarify whether the atypical antipsychotics caused such manic-like states or simply failed to prevent them. Presumably, bipolar patients would be at increased risk for this putative adverse event. Therefore, we evaluated the potential of olanzapine to exacerbate symptoms of mania compared to placebo during treatment of bipolar mania. METHODS: Two inpatient, double-blind, randomized trials investigating the efficacy of olanzapine 5-20 mg daily versus placebo for the treatment of acute mania were combined. Two hundred and fifty-four subjects participated (placebo n=129; olanzapine n=125) in the two studies. Severity of mania was quantified with the 11-item Young-Mania Rating Scale (Y-MRS). In a post-hoc analysis, after double-blind therapy up to 3 weeks, categorical comparison of olanzapine and placebo groups was made for any worsening and worsening by 10 or 20% from baseline Y-MRS scores (LOCF). RESULTS: The percentage of subjects with exacerbation at endpoint were: any worsening, placebo 37.7%, olanzapine 21.8% (P=0.005); >or=10% worsening, placebo 24.6%, olanzapine 14.5% (P=0.039); >or=20% worsening, placebo 15.6%, olanzapine 8.1% (P=0.064). CONCLUSION: Mania rating scores worsened for some patients during olanzapine therapy. However, this was significantly less common with olanzapine than with placebo. These controlled data suggest that clinical case reports of occurrence of 'mania' during treatment with olanzapine, and possibly those with other atypical antipsychotics, reflect exacerbation in the natural history of bipolar illness, rather than an adverse pharmacological effect. LIMITATIONS: Post-hoc analysis of pooled data from two different studies.

Adult↗
PubMed2003

Analgesic and placebo effects of thalamic stimulation.

Numerous clinical studies have reported successful relief of chronic pain with sensory thalamic stimulation. However, even with the extensive use of sensory thalamic stimulation as a clinical tool in the relief of chronic pain, the results are still inconsistent. This discrepancy could probably be explained by the fact that the majority of these studies are case reports or retrospective analyses, which have often used imprecise pain measurements that do not allow a rigorous statistical evaluation of pain relief. None of these studies measured the effect of stimulation on clinical pain for longer than a few hours per day, which is an important aspect considering that clinical pain can vary over time. Moreover, placebo controls are seldom included. In the current study, we measured patients' pain perception at home over a 2-week period, both during days of normal stimulation of the sensory thalamus and during days without stimulation. Patients also came to the laboratory to assess the effects of thalamic and placebo stimulation on clinical pain, experimental heat pain, innocuous air puff and visual stimulation. A potential relation between the perceived paresthesia and analgesic efficacy during thalamic and placebo stimulation was also explored. We found that thalamic stimulation significantly affected clinical and experimental pain perception, but that an important placebo component also exists. On the other hand, neither thalamic nor placebo stimulation affected air puff and visual ratings, suggesting that the effect applies specifically to pain and hence is not caused by a general change in attention. The level of paresthesia elicited during the placebo manipulation was also directly correlated with the degree of placebo pain relief. These results suggest that thalamic stimulation produces a small but significant reduction in pain perception, but that a significant placebo effect also exists.

Adult↗
PubMed1999

Are randomized control trial outcomes influenced by the inclusion of a placebo group?: a systematic review of nonsteroidal antiinflammatory drug trials for arthritis treatment.

Placebo groups are often included in randomized control trials evaluating drug therapy, yet we know little about the placebo effect. The purpose of our study was to evaluate how the presence of a placebo group in a randomized control trial (RCT) influences the patients' ratings of the efficacy of an active drug therapy and their reporting of its adverse effects. We identified studies published between 1966 and 1994 using MEDLINE. Randomized control trials evaluating acetylsalicylic acid, diclofenac, or indomethacin for the treatment of osteo or rheumatoid arthritis were included in our sample. Two investigators independently extracted data. Fifty-eight treatment arms met our inclusion criteria and were available for analysis. Twenty-five treatment arms evaluated a nonsteroidal antiinflammatory drug (NSAID) in placebo control trials and 33 in comparative trials. Using a logistic regression model to adjust for the differences between the evaluated drugs and between the types of arthritis, we found that patients receiving an NSAID in a placebo control trial were more likely to withdraw due to inefficacy (OR=1.3; 95% CI, 1.0 to 1.6; P=0.04). Using a similar model, withdrawals due to adverse effects were found to be more common when the NSAID was given in trials that did not include a placebo group (OR=1.5; 95% CI, 1.1 to 1.9; P=0.002) as were reports of cutaneous (OR=4.2; 95% CI, 1.7 to 9.9), gastrointestinal (OR=1.6; 95% CI, 1.3 to 2.0), and other types (OR=5.3; 95% CI, 3.8 to 7.4) of adverse effects. Although reports of central nervous system adverse effects were more frequent in the comparative trials, this difference was not significant. Including a placebo group in a RCT changes how patients rate the efficacy and adverse effects of their therapy. Our results highlight the need to consider the placebo effect in the design and analyses of clinical trials.

Aged↗
PubMed2000

Why use placebos in clinical trials? A narrative review of the methodological literature.

Researchers have a number of different options for their choice of control or comparison intervention in randomized trials. We surveyed the methodological literature looking for reasons why a researcher might choose to administer a placebo (i.e., a mimic intervention) to control subjects. Two implicit assumptions were that the issue of placebo is pertinent only to drug trials and that the nonplacebo effect of a treatment is the "real" or "true" effect. Explicit reasons given in the literature for the use of placebos were facilitating blinding and controlling for the placebo effect. The importance of the latter was often inadequately argued. Reasons to avoid placebos in controlled trials, other than ethics and feasibility, are that placebos do not inform real decisions, and may interfere with accurate estimation of effect size and with nonspecific aspects of treatment. Placebo-controlled trials have high internal validity but may be difficult to apply to clinical practice; the situation is reversed for trials without placebo control.

Double-Blind Method↗
PubMed1996

Comparative study of cetirizine and terfenadine versus placebo in the symptomatic management of seasonal allergic rhinitis.

BACKGROUND: Cetirizine is a new antihistamine with greater selectivity for the histamine H1 receptor and a low rate of hepatic metabolism. Cetirizine once daily is effective in the symptomatic treatment of seasonal and perennial allergic rhinitis and chronic idiopathic urticaria. OBJECTIVE: The efficacy and safety of cetirizine 10 mg qd, terfenadine 60 mg bid, and placebo were compared in patients with seasonal allergic rhinitis. METHODS: A multicenter, prospective, double-blind, randomized, parallel study was conducted for 2 weeks during the ragweed pollen season in patients with documented allergic rhinitis. Total symptom complex and total symptom complex plus nasal congestion scores, global efficacy, overall satisfaction, and adverse events were assessed at baseline and after 1 and 2 weeks of treatment. RESULTS: Of the 311 patients randomized to treatment, 283 completed the study. Cetirizine produced a marked improvement in symptoms scores compared with placebo after 1 week of therapy (P = .001). By the end of week 1, total symptom complex scores were improved by 37% with cetirizine compared with 29% for terfenadine, and 23% for placebo. An overall treatment effect was evident at week 1 (P = .0019), with marked differences between cetirizine and both placebo (P = .0004) and terfenadine (P = .0464) but not between terfenadine and placebo (P = .1215). A more marked treatment effect was evident during the first week of the study; this appeared to be related to spontaneous resolution of symptoms, since mean pollen counts derived for each patient declined significantly each week of the study. Therapy was generally well tolerated. Headache was the most common side effect in each group. Four patients on cetirizine, one on terfenadine, and two on placebo withdrew because of side effects. Somnolence was reported in 12 patients on cetirizine (P < .05), 2 on terfenadine, and 3 on placebo. CONCLUSION: Cetirizine produced a greater improvement in symptoms of seasonal allergic rhinitis than terfenadine or placebo.

Adolescent↗
PubMed2002

Are placebo controls necessary to test new antidepressants and anxiolytics?

One measure of a treatment's effectiveness is the regularity with which it proves superior to placebo. That measure also tells us about the consequences of using a treatment as a standard against which to test a new agent. To assess the frequency with which approved and presumably effective antidepressants and anxiolytics show statistical superiority over placebo, we reviewed placebo-controlled clinical trials of antidepressants and anxiolytics in a singularly large database free of publication bias. We evaluated clinical-trial data from the nine antidepressants approved by the FDA between 1985 and 2000. These trials comprised 10030 depressed patients who participated in 52 antidepressant clinical trials evaluating 93 treatment arms of a new or established antidepressant. Similarly, we examined clinical trials data from the 13 anxiolytics approved by the FDA between 1985 and 2000. These trials comprised 8,340 anxious patients, 40 anxiolytic clinical trials and 75 treatment arms of a new or established anxiolytic. Fewer than half (48%, 45/93) of the antidepressant treatment arms showed superiority to placebo. Among anxiolytics, 48% (36/75) of anxiolytic treatment arms showed superiority over placebo. These data suggest that conventional psychopharmacologic treatments for depression and anxiety are superior to placebo less than half the time and call into serious question the widely propagated notion that placebo controls can be dispensed with in clinical trials of these agents. Exclusion of placebo controls in favour of non-inferiority trials would result in a high likelihood that ineffective antidepressants and anxiolytics would be foisted on the public and, less dangerous but also problematic, that potentially effective agents would be missed.

Anti-Anxiety Agents↗
PubMed2000

A double-blind comparison of fluvoxamine versus placebo in the treatment of compulsive buying disorder.

Nondepressed outpatients with a compulsive buying disorder were recruited by advertisement and word of mouth for inclusion in a controlled treatment trial. Following a 1-week single-blind placebo washout, subjects were randomly assigned to fluvoxamine (n = 12) or placebo (n = 11). Subjects received fluvoxamine (up to 300 mg daily) or placebo for 9 weeks. There were few dropouts. Outcome measures included the Yale-Brown Obsessive-Compulsive Scale--Shopping Version (YBOCS-SV), three Clinical Global Impressions (CGI) ratings, the Hamilton Rating Scale for Depression (HRSD), and the Maudsley Obsessive-compulsive Inventory (MOI). At the conclusion of the trial, 50% of fluvoxamine recipients and 63.6% of placebo recipients achieved CGI ratings of "much" or "very much" improvement, while 33% of fluvoxamine recipients were "very much" improved compared with 18% of placebo recipients (by endpoint analysis). Subjects in both treatment cells showed improvement as early as the second week of the trial, and for most, improvement continued during the 9-week study. There were no significant differences between fluvoxamine- and placebo-treated subjects on any of the outcome measures, with the exception that fluvoxamine recipients achieved greater improvement than placebo recipients on the MOI (p = .02). Adverse experiences were more frequent in the group receiving fluvoxamine, particularly nausea, insomnia, decreased motivation, and sedation. We conclude that in a short-term treatment trial of compulsive buying, subjects receiving fluvoxamine or placebo respond similarly.

Adult↗
PubMed2000

Response to placebo among bipolar I disorder patients experiencing their first manic episode.

BACKGROUND: The first episode of an illness may respond differently to any treatment compared to multiple episodes of the same illness. This study details the treatment response of six first-episode manic patients who participated in a previously reported study of 139 subjects comparing olanzapine to placebo in bipolar I mania (Tohen M, Sanger TM, McElroy SL, Tollefson GD, Chengappa KNR, Daniel DG. Olanzapine versus placebo in the treatment of acute mania. Am J Psychiatry 1999; 156: 702-709). METHODS: Six first-episode subjects participated in a 3-week double-blind, random assignment, parallel group, placebo-controlled study of olanzapine for bipolar mania. The Young Mania Rating Scale (Y-MRS), Clinical Global Impression, and Hamilton Depression ratings were administered weekly. Lorazepam as rescue medication was permitted for the first 10 days. RESULTS: Five subjects were randomized to placebo and one to olanzapine. Two subjects (40%) with psychotic mania (who also had their first-illness episode) were assigned to placebo and responded with greater than 50% reduction in the Y-MRS score and also remitted in 3 weeks. Another placebo-assigned subject had a 46% reduction in the Y-MRS scores, and two placebo-assigned subjects worsened. The olanzapine-assigned subject had a 44% reduction in the Y-MRS score. In contrast, 34 of 69 (48.6%) multiple-episode olanzapine subjects responded and 14 of 61 (23.0%) of placebo-treated subjects did. CONCLUSIONS: This preliminary data set suggest there may be differences in treatment response between first-illness episode versus multi-episode bipolar manic subjects. Larger numbers of subjects with these illness characteristics are needed to either confirm or refute this suggestion.

Acute Disease↗
PubMed1987

Blinding, unblinding, and the placebo effect: an analysis of patients' guesses of treatment assignment in a double-blind clinical trial.

We administered a questionnaire to assess maintenance of patients' blindness at the end of a double-blind clinical trial of Osmotic Release Oral System phenylpropanolamine (PPA) vs. placebo in mild obesity. Seventy-four percent of placebo participants and 43% of PPA participants guessed their treatment correctly. Appetite control was the most frequently reported basis for guessing PPA, even by placebo participants. Lack of adverse drug reactions was the most frequently reported basis for guessing placebo, even by PPA participants. Participants receiving either PPA or placebo and guessing PPA lost more weight, had less diet difficulty, and had more adverse drug reactions than had participants receiving either PPA or placebo and guessing placebo. Although blindness was probably maintained in the PPA group, the placebo group seems to have been, at least at the study's end, unblinded. These results suggest that in double-blind studies, differences in outcome or incidence of adverse drug reactions may act as unblinding factors.

Body Weight↗
PubMed1994

Placebo as a treatment for depression.

The placebo response rate in depression consistently falls between 30 and 40%. Among more severely depressed patients antidepressants offer a clear advantage over placebo; among less severely depressed patients and those with a relatively short episode duration the placebo response rate is close to 50% and often indistinguishable from the response rate to antidepressants. In the treatment of depression none of the psychotherapies have consistently been shown to offer an advantage over pill placebo. This is not entirely surprising given the fact that the common, and arguably the therapeutic, features of the psychotherapies (expectation of improvement, support, mobilization of hope) are provided with pill placebo treatment. The placebo response in depression has been viewed as a nuisance rather than as a therapeutic and research opportunity. I propose that the initial treatment for selected depressed patients should be four to six weeks of placebo. Patients so treated should be informed that the placebo pill contains no drug but that this treatment can be helpful.

Depressive Disorder↗
PubMed2000

One-year treatment of obesity: a randomized, double-blind, placebo-controlled, multicentre study of orlistat, a gastrointestinal lipase inhibitor.

OBJECTIVE: To assess the efficacy and tolerability of orlistat (Xenical) in producing and maintaining weight loss over a 12-month period. DESIGN: Patients were randomized to double-blind treatment with either orlistat 120 mg or placebo three times daily, in conjunction with a low-energy diet, for 12 months. SETTING: Five centres in the UK. SUBJECTS: 228 obese adult patients with body mass index between 30 and 43 kg/m2 and mean weight 97 kg (range 74-144 kg). INTERVENTIONS: All patients were prescribed a low-energy diet, providing 30% of energy from fat, designed to produce an individually tailored energy deficit of approximately 600 kcal/day, for a run-in period of 4 weeks and then 12 months, plus orlistat 120 mg or placebo three times daily. MAIN OUTCOME MEASURES: Change in body weight (the primary efficacy parameter), waist circumference and adverse events were reviewed regularly, together with serum lipids, insulin, glucose and plasma levels of fat-soluble vitamins and beta carotene. RESULTS: Based on an intent-to-treat analysis, after 1 y of treatment patients receiving orlistat had lost an average of 8.5% of their initial body weight compared with 5.4% for placebo-treated patients; 35% of the orlistat group lost at least 5% of body weight compared with 21% of the placebo group (P < 0.05), and 28% and 17%, respectively (P = 0.04) lost at least 10% of body weight. Orlistat-treated patients showed significant decreases (P < 0.05) in serum levels of total cholesterol, low density lipoprotein cholesterol, and in the low density lipoprotein: high density lipoprotein ratio in comparison with placebo. Both groups had similar adverse-event profiles, except for gastrointestinal events, which were 26% more frequent in the orlistat group but were mostly mild and transient. To maintain normal plasma levels of fat-soluble vitamins, supplements of vitamins A, D and E were given to 1.8%, 8.0% and 3.6%, respectively, of orlistat-treated patients, compared with 0.9% of placebo-treated patients for each vitamin type. After 1 y, the decrease in vitamin E and beta carotene was significantly greater in orlistat-treated patients compared with those receiving placebo (P < 0.001). No significant change was found in the mean vitamin E:total cholesterol ratio in either group after 52 weeks. CONCLUSIONS: Orlistat, in conjunction with a low-energy diet, produced greater and more frequent significant weight loss than placebo during 1 y of treatment. One-third of orlistat-treated patients achieved clinically relevant weight loss (> or = 5% initial body weight). There was also an improvement in relevant serum lipid parameters. Fat-soluble vitamin supplements may be required during chronic therapy. Orlistat was well tolerated and offers a promising new approach to the long-term management of obesity.

Adult↗