Mechanisms of Perceived Treatment Assignment and Subsequent Expectancy Effects in a Double Blind Placebo Controlled RCT of Major Depression

Objective: It has been suggested that patients' perception of treatment assignment might serve to bias results of double blind randomized controlled trials (RCT). Most previous evidence on the effects of patients' perceptions and the mechanisms influencing these perceptions relies on cross-sectional associations. This re-analysis of a double blind, placebo controlled RCT of pharmacological treatment of major depression set out to gather longitudinal evidence on the mechanism and effects of patients' perceived treatment assignment in the pharmacological treatment of major depression.Methods: One-hundred eighty-nine outpatients with DSM-IV diagnosed major depression were randomized to SAMe 1,600–3,200 mg/d, escitalopram 10–20 mg/days, or placebo for 12 weeks. Data on depressive symptoms (17-item Hamilton Depression Scale; HDRS-17), adverse events and patients' perceived treatment assignment was collected at baseline, week 6, and week 12. The re-analysis focused on N = 166 (out of the originally included 189 participants) with available data on perceived treatment assignment.Results: As in the parent trial, depressive symptoms (HDRS-17) significantly decreased over the course of 12 weeks and there was no difference between placebo, SAMe or escitalopram. A significant number of patients changed their perceptions about treatment assignment throughout the trial, especially between baseline and week 6. Improvement in depressive symptoms, but not adverse events significantly predicted perceived treatment assignment at week 6. In turn, perceived treatment assignment at week 6, but not actual treatment, predicted further improvement in depressive symptoms at week 12.Conclusions: The current results provide longitudinal evidence that patients' perception of treatment assignment systematically change despite a double blind procedure and in turn might trigger expectancy effects with the potential to bias the validity of an RCT.Parent study grant number: R01 AT001638 Parent study ClinicalTrials. gov Identifier: NCT0010145

Effects of stress beliefs on the emotional and biological response to acute psychosocial stress in healthy men

Background Negative beliefs about stress (e.g., “stress is bad”) constitute an independent risk factor for increased morbidity and mortality. One potential underlying mechanism are altered responses to acute psychosocial stress. The aim of this study was to investigate whether beliefs about stress are associated with physiological and endocrine stress response patterns. Methods A total of N = 77 healthy adults were randomised to an experimental and a placebo control group and were subsequently exposed to the Trier Social Stress Test (TSST). Stress beliefs were measured before and after a psychological manipulation aiming at fostering more balanced stress beliefs or a placebo manipulation. Self-reported stress was measured four times before/after the TSST, heart rate was assessed continuously, and cortisol was assessed eight times before/after the TSST. Results There was a significant decrease in negative stress beliefs (p < .001) and increase in positive stress beliefs (p < .001) in participants in the experimental condition, which was absent in participants in the placebo condition. The participants in the experimental group had more pronounced self-reported stress reactions (p = .028) while at the same time also showing more pronounced stress recoveries (p = .036). The findings regarding cortisol were mixed. Conclusions More balanced stress beliefs appeared to be associated with more efficient subjective responses to acute psychosocial stress. These findings attest to a potential mechanism translating negative stress beliefs into ill health while at the same time outlining targets for psychological interventions

The Beliefs About Stress Scale (BASS): Development, reliability, and validity

Evidence from population and experimental studies suggests that laypersons’ beliefs about stress influence mental and physical health. Yet, studies so far have solely relied on psychometrically not evaluated instruments to measure stress beliefs. Standardized assessment is needed to facilitate research on this novel and promising construct in stress research. This study reports on the development and psychometric evaluation of a new questionnaire to assess stress beliefs: The Beliefs About Stress Scale (BASS). An item pool of 24 statements on stress beliefs was administered to N = 455 university students at the beginning of term via an online survey. Additionally, participants’ subjective stress levels, optimism, pessimism, neuroticism and somatosensory amplification were assessed. A subsample of N = 216 participants was reassessed during end of term exams 6 to 8 weeks later. Using a split sample procedure, both exploratory and confirmatory factor analysis suggested 3 dimensions of stress beliefs: negative stress beliefs, positive stress beliefs, controllability. The scales showed good to acceptable internal consistency (Cronbach α = .73–.87) and retest-reliability (rtt6-8 = .61–.81). Correlations with optimism, pessimism, neuroticism and somatosensory amplification (r = .15–.47) indicated high to medium discriminant validity. Moreover, baseline negative stress beliefs appeared to be associated with an increased level of stress at end of term exams 6 to 8 weeks later by statistical trend (β = .11; p = .062). Stress beliefs appear to be multidimensional and stable over time. The BASS offers a promising new way to assess stress beliefs via a brief, psychometrically evaluated questionnaire

The Effects of Stress Beliefs on Daily Affective Stress Responses

Background Negative beliefs about the effects of stress have been associated with poorer health and increased mortality. However, evidence on the psychological mechanisms linking stress beliefs to health is scarce, especially regarding real-life stress. Purpose The aim of the current study was to investigate the effects of stress beliefs on affect in the daily stress process in a population prone to health-impairing effects of stress: university students. Methods Using daily diaries, 98 university students reported on daily perceived social and work-related stressors as well as positive and negative affect for 10 consecutive days. Stress beliefs, depressive and anxiety symptoms, neuroticism, and demographic variables were assessed prior to the daily diary phase. Results Hierarchical linear models revealed a significant cross-level interaction between negative stress beliefs and the association of daily social stressors with negative affect (B = 0.24; 99% confidence interval [CI] = 0.08–0.41, p &lt; .001). When experiencing social stress, participants who held high negative stress beliefs had higher daily negative affect (simple slope = 4.09; p &lt; .001); however, for participants who held low negative stress beliefs the association between daily social stress and daily negative affect was considerably smaller (simple slope = 2.12; p &lt; .001). Moreover, individuals believing stress to be controllable showed higher positive affect throughout the 10-day daily diary phase. Conclusions Negative stress beliefs were found to moderate the affective response to daily real-life stressors. Given the established relationship between affect and health, this study provides initial evidence of psychological mechanisms linking stress beliefs to health

The effects of patients' expectations on surgery outcome in total hip and knee arthroplasty: a prognostic factor meta-analysis

Patients' expectations are among the most frequently studied psychological prognostic factors in total knee and hip arthroplasty (TKA/THA). So far, however, evidence on the effect of patients' preoperative expectations on surgery outcome is inconclusive. Heterogeneity of expectation constructs and the use of psychometrically not evaluated measurement instruments have constituted major obstacles for the integration of the current literature. Using a theory-based model of expectation constructs , this meta-analysis set out to disentangle the conflicting results in the current literature. Systematic literature searches yielded k = 46 studies (N = 10,465) that reported associations of preoperative expectations with postoperative pain, functioning and disability, and satisfaction. Random effects meta-analysis revealed a robust small association (r = .16; 95% CI .13, .19) between patients' positive preoperative expectations and better postoperative outcomes. This effect did not differ between THA and TKA, different outcome categories and different follow-up periods. Studies using psychometrically evaluated expectation measures reported significantly higher effects (r = .19; 95% CI .16, .22). Whether this effect varies among different expectation constructs remains unclear. High-quality studies using validated, multidimensional expectation measures are needed to further understand the role of different expectation constructs in THA and TKA surgery

The Treatment Expectation Questionnaire (TEX-Q): Validation of a generic multidimensional scale measuring patients' treatment expectations.

BackgroundPatients' expectations, as a central mechanism behind placebo and nocebo effects, are an important predictor of health outcomes. Yet, theoretically based generic assessment tools allowing for an integrated understanding of expectations across conditions and treatments are lacking. Based on the preliminary 35-item version, this study reports the development and validation of the Treatment Expectation Questionnaire (TEX-Q), a generic, multidimensional self-report scale measuring patients' expectations of medical and psychological treatments.MethodsThe TEX-Q was developed in a validation sample of n = 251 patients undergoing different treatments using exploratory factor analyses and item analyses, as well as analysis of convergent and divergent validity. Confirmatory factor analysis was conducted in an independent sample of n = 303 patients undergoing cancer treatment. Two-weeks test-retest reliability was assessed in n = 28 psychosomatic outpatients.ResultsFactor analyses revealed six theoretically founded stable subscales. The TEX-Q assesses expectations of treatment benefit, positive impact, adverse events, negative impact, process and behavioural control with a total of 15 items. Results for the subscales and the sum score indicated good internal consistency (α = .71-.92), moderate to high test-retest reliability (r = .39-.76) as well as good convergent validity with regard to other expectation measures (r = .42-.58) and divergent validity with regard to measures of generalized expectations (r ConclusionsWhile further validation is needed, the results suggest that the TEX-Q is a valid and reliable scale for the generic, multidimensional assessment of patients' treatment expectations. The TEX-Q overcomes constraints of ad-hoc and disease-specific scales, while allowing to compare the impact of different expectation constructs across conditions and treatments