This dissertation covered several relevant cycles of placebo research with the main aim to optimize placebo effects in medical contexts. Firstly, a literature review described how the immune system... Show moreThis dissertation covered several relevant cycles of placebo research with the main aim to optimize placebo effects in medical contexts. Firstly, a literature review described how the immune system can be impacted by placebo effects and their underlying learning theories. In the following chapter, these learning theories were integrated to form an optimal research design by means of pharmacological conditioning to fit a specific patient group: children with juvenile idiopathic arthritis. Secondly, this dissertation focused on developing placebo information strategies to harness placebo beliefs and educate persons about the relevancy of placebo effects in practice. These insights are valuable because treatment expectations can have a positive or negative effect on treatment outcomes. Finally, insights from placebo learning theories and placebo information strategies were combined in an integrative experimental research design. This research design employed a more ethical form of placebo use because participants were made aware of placebos, called open-label placebos. In this last study we demonstrated that open-label placebo analgesia can be induced by combining learning theories and placebo information strategies. Altogether, this dissertation provided insights in learning mechanisms, communication strategies, and research paradigms that involve the optimization of placebo effects in medical context. Show less
Insight in the underlying mechanisms of sexual motivation is essential to understand disorders in sexual desire and such understanding may be helpful in the development of new and effective... Show moreInsight in the underlying mechanisms of sexual motivation is essential to understand disorders in sexual desire and such understanding may be helpful in the development of new and effective psychological and pharmacological interventions, since empirically validated treatments are lacking for female sexual interest/arousal disorder as well as hypersexuality and related disorders. Because much sexual behaviour is thought to be acquired through learning, and given the specific hypothesis that classical conditioning plays an etiological role in the development of sexual dysfunction, research in the area of classical conditioning of human sexual arousal is warranted. In the first part of this thesis, experimental studies on sexual conditioning and extinction are described. Further insights in human sexual motivation and behaviour require looking more closely at the pathway of information between stimulus and response and considering how these processes are embedded within other (higher-level) processes and higher order brain structures such as frontal regions, known to be involved in emotional processing and regulation. The second part of this thesis describes studies on the influence of emotion regulation strategies on the expectation of sexual reward, and one fMRI study on the influence of acute-stress on deliberate emotion regulation during the processing of sexual stimuli. Show less