RESUMO
BACKGROUND: Patients receiving placebo in clinical trials often report side-effects (nocebo effects), but contributing factors are still poorly understood. PURPOSE: Using a sham trial of the cognition-enhancing "smart pill" Modafinil we tested whether medication beliefs and other psychological factors predicted detection and attribution of symptoms as side-effects to placebo. METHODS: Healthy students (n = 201) completed measures assessing beliefs about medication, perceived sensitivity to medicines, negative affectivity, somatization, and body awareness; 66 were then randomized to receive Deceptive Placebo (told Modafinil-given placebo, 67 to Open Placebo (told placebo-given placebo, and 68 to No Placebo. Memory and attention tasks assessed cognitive enhancement. Nocebo effects were assessed by symptom checklist. RESULTS: More symptoms were reported in the Deceptive Placebo condition (M = 2.65; SD = 2.27) than Open Placebo (M = 1.92; SD = 2.24; Mann-Whitney U = 1,654, z = 2.30, p = .022) or No Placebo (M = 1.68; SD = 1.75, Mann-Whitney U = 1,640, z = 2.74, p = .006). Participants were more likely to attribute symptoms to Modafinil side-effects if they believed pharmaceuticals to be generally harmful (incidence rate ratio [IRR] = 1.70, p = .019), had higher perceived sensitivity to medicines (IRR = 1.68, p = .011), stronger concerns about Modafinil (IRR = 2.10, p < .001), and higher negative affectivity (IRR = 2.37, p < .001). CONCLUSIONS: Beliefs about medication are potentially modifiable predictors of the nocebo effect. These findings provide insight into side-effect reports to placebo and, potentially, active treatment.
Assuntos
Efeitos Colaterais e Reações Adversas Relacionados a Medicamentos , Cognição , Humanos , Modafinila/efeitos adversos , Efeito Nocebo , Preparações FarmacêuticasRESUMO
OBJECTIVES: Attribution of symptoms as medication side effects is informed by pre-existing beliefs about medicines and perceptions of personal sensitivity to their effects (pharmaceutical schemas). We tested whether (1) pharmaceutical schemas were associated with memory (recall/recognition) for side effect information (2) memory explained the attribution of a common unrelated symptom as a side effect. DESIGN: In this analogue study participants saw the patient leaflet of a fictitious asthma drug listing eight side effects. MAIN OUTCOME MEASURES: We measured recall and recognition memory for side effects and used a vignette to test whether participants attributed an unlisted common symptom (headache) as a side effect. RESULTS: Participants who perceived pharmaceuticals as more harmful in general recalled fewer side effects correctly (rCorrect Recall = -.273), were less able to differentiate between listed and unlisted side effects (rRecognition Sensitivity = -.256) and were more likely to attribute the unlisted headache symptom as a side effect (rside effect attribution = .381, ps < .01). The effect of harm beliefs on side effect attribution was partially mediated by correct recall of side effects. CONCLUSION: Pharmaceutical schemas are associated with memory for side effect information. Memory may explain part of the association between pharmaceutical schemas and the attribution of unrelated symptoms as side effects.
Assuntos
Efeitos Colaterais e Reações Adversas Relacionados a Medicamentos , Conhecimentos, Atitudes e Prática em Saúde , Memória , Adulto , Antiasmáticos/efeitos adversos , Antiasmáticos/uso terapêutico , Asma/tratamento farmacológico , Feminino , Humanos , Masculino , Rememoração Mental , Pessoa de Meia-Idade , Folhetos , Educação de Pacientes como Assunto , Reconhecimento Psicológico , Inquéritos e Questionários , Adulto JovemRESUMO
OBJECTIVE: Some perceived medication side effects may be 'normal' symptoms that patients misattribute to the medication. Using an analogue approach, we tested if medication beliefs predict whether participants misattribute a headache as a side effect and subsequently intend to stop medication. METHODS: We recruited 690 participants, 223 reporting a past asthma diagnosis. They received information about asthma and Molair, a fictitious asthma treatment modeled on a licensed treatment (montelukast). We varied the description of efficacy and side effects (which did not include headache). Pre-exposure to this information, participants completed the Beliefs about Medicine Questionnaire (BMQ)-General and the Perceived Sensitivity to Medicines Scale (PSM), post-exposure they completed the BMQ-Specific. Participants were asked to imagine they experienced a headache while taking Molair. Finally, they rated whether the headache was a side effect (misattribution) and if they would stop taking Molair (behavioral intention). RESULTS: Nearly a quarter (170) of participants misattributed the headache to Molair and 69 (10%) subsequently intended to stop Molair. Both outcomes were predicted by general and specific medication beliefs. Odds of misattribution (m) and behavioral intention (i) increased with higher General Harm (ORm=1.90, ORi=2.72), General Overuse (ORm=1.74, ORi=1.56) and Molair Concern beliefs (ORm=1.52, ORi=1.78, all p<.01), but decreased with General Benefit (ORm=0.72, ORi=0.53) and Molair Necessity beliefs (ORm=0.72, ORi=0.70, all p<.05). CONCLUSION: Symptom misattribution and subsequent intentions to stop Molair were predicted by pre-exposure beliefs about medicines in general and post-exposure beliefs about Molair. Patients with negative medication beliefs may be prone to misattribute symptoms and subsequently stop medication.