Background In pharmacological conditioning associations are formed between the effects of medication and contextual factors related to the medication. Pharmacological conditioning with placebo... Show moreBackground In pharmacological conditioning associations are formed between the effects of medication and contextual factors related to the medication. Pharmacological conditioning with placebo medication can result in comparable treatment effects and reduced side effects compared to regular treatment in various clinical populations, and may be applied to achieve enhanced drug effects. In the current study protocol, pharmacological conditioning is applied to achieve enhanced treatment effects in patients with recent-onset rheumatoid arthritis (RA). The results from this study broaden the knowledge on the potential of pharmacological conditioning and provide a potential innovative treatment option to optimize long-term pharmacological treatment effectiveness for patients with inflammatory conditions, such as recent-onset RA. Methods A multicenter, randomized controlled clinical trial is conducted in patients with recent-onset RA. Participants start on standardized pharmacological treatment for 16 weeks, which consists of methotrexate (MTX) 15 mg/week and a tapered schedule of prednisone 60 mg or 30 mg. After 4 months, participants in clinical remission (based on the rheumatologist's opinion and a targeted score below 1.6 on a 44-joint disease activity score (DAS44)) are randomized to 1 of 2 groups: (1) the control group (C), which continues with a standardized treatment schedule of MTX 15 mg/week or (2) the pharmacological conditioning group (PC), which receives an MTX treatment schedule in alternating high and low dosages. In the case of persistent clinical remission after 8 months, treatment is tapered and discontinued linearly in the C group and variably in the PC group. Both groups receive the same cumulative amount of MTX during each period. Logistic regression analysis is used to compare the proportion of participants with drug-free clinical remission after 12 months between the C group and the PC group. Secondary outcome measures include clinical functioning, laboratory assessments, and self-reported measures after each 4-month period up to 18 months after study start. Discussion The results from this study broaden the knowledge on the potential of pharmacological conditioning and provide a potential innovative treatment option to optimize long-term pharmacological treatment effectiveness in patients with inflammatory conditions, such as recent-onset RA. Show less
Hamstra, D.A.; Kloet, E.R. de; Tollenaar, M.; Verkuil, B.; Manai, M.; Putman, P.; Does, W. van der 2016
RATIONALE\nThe processing of emotional information is affected by menstrual cycle phase and by the use of oral contraceptives (OCs). The stress hormone cortisol is known to affect emotional... Show moreRATIONALE\nThe processing of emotional information is affected by menstrual cycle phase and by the use of oral contraceptives (OCs). The stress hormone cortisol is known to affect emotional information processing via the limbic mineralocorticoid receptor (MR).\nOBJECTIVES\nWe investigated in an exploratory study whether the MR-genotype moderates the effect of both OC-use and menstrual cycle phase on emotional cognition.\nMETHODS\nHealthy premenopausal volunteers (n=93) of West-European descent completed a battery of emotional cognition tests. Forty-nine participants were OC users and 44 naturally cycling, 21 of whom were tested in the early follicular (EF) and 23 in the mid-luteal (ML) phase of the menstrual cycle.\nRESULTS\nIn MR-haplotype 1/3 carriers, ML women gambled more than EF women when their risk to lose was relatively small. In MR-haplotype 2, ML women gambled more than EF women, regardless of their odds of winning. OC-users with MR-haplotype 1/3 recognised fewer facial expressions than ML women with MR-haplotype 1/3.\nCONCLUSION\nMR-haplotype 1/3 carriers may be more sensitive to the influence of their female hormonal status. MR-haplotype 2 carriers showed more risky decision-making. As this may reflect optimistic expectations, this finding may support previous observations in female carriers of MR-haplotype 2 in a naturalistic cohort study. Show less
Kowal, M.; Steenbergen, H. van; Colzato, L.S.; Hazekamp, A.; Van der Wee, N.; Manai, M.; ... ; Hommel, B. 2015
The present study investigated the relationship between objective temperature and subjective temperature preferences in predicting performance in simple and complex cognitive tasks. We assessed the... Show moreThe present study investigated the relationship between objective temperature and subjective temperature preferences in predicting performance in simple and complex cognitive tasks. We assessed the impact of room temperature (warm and cold) on the ability to “update” (and monitor) working memory (WM) representations in two groups of participants, who differed in their subjective temperature preferences (warm-preferred vs. cold-preferred). Participants performed an N-back task in which conditions (1-back and 2-back) differ in their WM load and cognitive demands. Results showed that the preferred, but not the objective temperature predicts WM performance in the more resource-demanding (the 2-back) condition. We propose that subjective preferences are more reliable predictors of performance than objective temperature and that performing under the preferred temperature may counteract “ego-depletion” (i.e., reduced self-control after an exhausting cognitive task) when substantial cognitive control is required. Our findings do not only favor a cognitive approach over the environmental/physical approaches dominating the research on cognition–environment interactions, but they also have important, straightforward practical implications for the design of workplaces. Show less
Kowal, M.A.; Hazekamp, A.; Colzato, L.S.; Steenbergen, H. van; Wee, N.J.A. van der; Durieux, J.; ... ; Hommel, B. 2014
Rationale Cannabis users often claim that cannabis has the potential to enhance their creativity. Research suggests that aspects of creative performance might be improved when intoxicated with... Show moreRationale Cannabis users often claim that cannabis has the potential to enhance their creativity. Research suggests that aspects of creative performance might be improved when intoxicated with cannabis; however, the evidence is not conclusive. Objective The aim of this study was to investigate the acute effects of cannabis on creativity. Methods We examined the effects of administering a low (5.5 mg delta-9-tetrahydrocannabinol [THC]) or high (22 mg THC) dose of vaporized cannabis vs. placebo on creativity tasks tapping into divergent (Alternate Uses Task) and convergent (Remote Associates Task) thinking, in a population of regular cannabis users. The study used a randomized, double-blind, between-groups design. Results Participants in the high-dose group (n = 18) displayed significantly worse performance on the divergent thinking task, compared to individuals in both the low-dose (n = 18) and placebo (n = 18) groups. Conclusions The findings suggest that cannabis with low potency does not have any impact on creativity, while highly potent cannabis actually impairs divergent thinking. Show less
