Disease relevance of Placebo Effect

• Expectation and dopamine release: mechanism of the placebo effect in Parkinson's disease [1].
• The model describes disease progression without treatment, the placebo effect, and the effect of tacrine as a function of daily dose [2].
• We are currently running a phase III double-blind trial with high-dose pamidronate for progressive painful metastatic bone disease to exclude any placebo effect and observer bias [3].
• Vitamin C, the placebo effect, and the common cold: a case study of how preconceptions influence the analysis of results [4].
• This study shows that there was an important placebo effect when treatment of angina pectoris was evaluated and that pindolol significantly reduced myocardial oxygen demand but evidence of ischemia was not significantly reduced [5].

Psychiatry related information on Placebo Effect

• PURPOSE: A population pharmacokinetic-pharmacodynamic model accounting for placebo effect was used to relate nicotine concentration and enforced smoking cessation craving score measured by the Tiffany rating scale short form [6].
• In each case, sequential replacement of drugs (Ritalin and Dexedrine) with placebos demonstrated placebo effects of the drugs; behavior therapy, alone and in combination with drugs, was effective in controlling hyperactive behaviors [7].
• Future research also should explore the moderating influences of the environmental context and of individual difference factors on placebo effects of smoking and other nicotine intake [8].
• Moreover, the study proved that the extent of the placebo effect in a population is inversely dependent on the level of neuroticism measured by Eysenck Personality Inventory, and directly dependent on the number of anginal attacks in the period before administration of the drug [9].

High impact information on Placebo Effect

• This study indicates that the effectiveness of nicotine gum is not due to a placebo effect and that it is related to dose [10].
• Other neurotransmitters or neuropeptides, however, are also likely to be involved in mediating the placebo effect (e.g. opioids in pain disorders, serotonin in depression) [11].
• RESULTS: On the basis of net responses to m-chlorophenylpiperazine (placebo effects subtracted from drug effects), patients with SAD exhibited blunted prolactin responses and less sadness than normal controls in response to the drug [12].
• CONCLUSIONS: Bright light therapy had a specific antidepressant effect beyond its placebo effect, but it took at least 3 weeks for a significant effect to develop [13].
• DESIGN: Double-blind randomized comparison of MCPP (0.1 mg/kg, intravenously, administered over 20 minutes) and placebo effects in patients and healthy subjects [14].

Chemical compound and disease context of Placebo Effect

• Using a stringent definition of placebo effect, we examined the frequency, temporal development, and stability of improvements during placebo treatment over 6 months in a large placebo-controlled trial of deprenyl and tocopherol in early Parkinson's disease (DATATOP) [15].
• Ménière's disease: lithium treatment (demonstration of placebo effect in a doubleblind cross-over trial) [16].

Biological context of Placebo Effect

• Suggested mechanisms contributing to the clinical benefit of EECP include improvement in endothelial function, promotion of coronary collateralization, enhancement of ventricular function, peripheral effects similar to those observed with regular physical exercise, and nonspecific placebo effects [17].
• Bromazepam and chlorprothixene are both superior to placebo in generalized anxiety states treated in general practice, but spontaneous improvements/placebo effects are substantial [18].
• Inhalation of 1 mg of fenoterol produced effective bronchodilatation, which was more than a placebo effect and was comparable with the responses achieved with other known effective bronchodilators given by inhalation [19].
• However, control patients also showed significant improvement in NYHA class by 6 months but showed no improvement in objective measurements (VO2, 6-minute walk distance, left ventricular ejection fraction, and norepinephrine levels), consistent with a placebo effect [20].
• Research directed toward evaluation of various TMD treatment modalities is particularly controversial due to cyclical fluctuation of symptoms, high rates of spontaneous remission, and possibility of placebo effect interference [21].

Anatomical context of Placebo Effect

• Interestingly, there is also placebo-induced dopamine release in the ventral striatum, which establishes a connection between the placebo effect and reward mechanisms [22].
• Ultradian chronomodulation by melatonin of a Placebo effect upon human killer cell activity [23].
• The authors argue that placebo-induced dopamine release in limbic structures, particularly in the nucleus accumbens, could also be a major biochemical substrate for the placebo effect encountered in other medical disorders [24].

Associations of Placebo Effect with chemical compounds

• Our findings indicate that the placebo effect in PD is powerful and is mediated through activation of the damaged nigrostriatal dopamine system [1].
• Oxygen therapy during exercise in patients who are not hypoxemic at rest should be done only when benefits cannot be attributed to a placebo effect of O2 therapy [25].
• The placebo effects associated with tacrine and placebo treatment were similar in magnitude and time course [26].
• In all 10 patients followed over a long term, oral diltiazem caused persistent improvement in exercise performance at 12 to 20 weeks, without evidence of placebo effects [27].
• By contrast, ketorolac conditioning together with expectation cues elicited a placebo effect that was blocked by naloxone only partially [28].

Gene context of Placebo Effect

• Failure to demonstrate a relationship between GHRH dose and changes in growth velocity might be explained by the combination of a placebo effect, insufficient frequency of GHRH administration and heterogeneity of the population [29].
• It was apparent that the effect determined after GH therapy in part was due to a placebo effect [30].
• This course is remarkably better than that of other children with CF treated without Intralipid in Auckland in the same period, though a placebo effect cannot be discounted [31].
• Two highly reliable scales, the Placebo Effect Scale (PES) and the Side Effect Scale (SES) were derived from the Placebo Test and served as dependent variables [32].
• PURPOSE: To compare self-regulation of low-frequency EEG components (slow cortical potentials, SCPs) with other methods of seizure control for patients with drug-refractory partial epilepsy and to separate the real anticonvulsive effect from placebo effects [33].

Analytical, diagnostic and therapeutic context of Placebo Effect

• Also, because no placebo control group was utilized, the authors of that study could not rule out the possibility that the apparent therapeutic effect from fluoxetine was the result of the placebo effect [34].
• This study of the effects of transcutaneous nerve stimulation (TNS) on 20 wrists of 11 men with rheumatoid arthritis was designd to make an objective assessment of pain and also to evaluate placebo effects [35].
• Recent clinical trials of secretin in children with autism showed robust placebo effects and no benefit of secretin over placebo [36].
• The drug seems to affect favourably the working capacity and the ECG on exercise for a longer period than NTG while we do not observe a placebo effect [37].
• METHODS: Thomsen et al (Arch Otolaryngol 1981;107:271-7) reported on the placebo effect in surgery for Meniere's disease in a controlled double-blind study [38].

References