Dissociative symptoms refer to disturbances in the integration of thoughts, feelings, and experiences into consciousness and memory. They overlap with schizotypical features, notably paranoid thinking. In recent studies, I found evidence that labile sleep-wake cycles a) lead to dreamlike mentation invading the waking state, b) produce memory failures, and c) fuel dissociative symptoms. This pattern of findings may inspire new treatments for dissociative symptoms (e.g., interventions that focus on normalization of the sleep-wake cycle), which is important because dissociative symptoms are notoriously recalcitrant to pharmacological and psychotherapeutic interventions. In this proposal, I aim to study the mechanisms underlying the link between sleep problems, dissociative symptoms, and paranoid thinking. One candidate mechanism might be emotional memory processing during REM sleep. I propose to conduct three studies; 1) a cross-sectional study to look at the correlations between dissociation, paranoid thinking, sleep aberrations, and memory measures; 2) a sleep deprivation experiment to test whether sleep disruption per se induces dissociative symptoms, paranoid thinking, and deteriorated emotional processing, and 3) a Cognitive Behavioural Therapy (CBT) intervention study aimed at sleep normalization to explore whether sleep improvement reduces dissociative symptoms and paranoid thinking through the improvement of emotional memory processing.

More and more people in our society are experiencing prolonged stress. Although it is known that stress affects memory, the impact on active forgetting remains a question. Our research showed that acute stress impaired active forgetting, depending on the strength of the memories. On the other hand, mindfulness improved the ability to control intentional memory. These findings contribute to our understanding of how the healthy brain actively manages memories, which factors can cause control to fail, and how we can enhance it. This has implications for the development of therapeutic interventions aimed at improving memory control.

The main source of overeating in obesity is cued overeating. Emotional and habitual overeating are forms of cued overeating and the main hypothesis of the present project is that cued, emotional and habitual overeating in obesity will extinguish trough extinction training. Three sets of studies will be done. The Dutch Diet Database will be started, in which 1000 dieters are followed prospectively. At baseline, genetic vulnerability, cue reactivity, negative affect, reward sensitivity and response inhibition will be measured. They will be followed and classified in unsuccessful and successful dieters (short term) and weight loss maintainers and regainers (long term). Predictors of weight loss success will be studied. A second series of studies is a set of experimental studies into the basic mechanisms of cued overeating: its classically conditioned nature and ways to extinction. The third study is an intervention: extinction training. It is hypothesized that unsuccessful dieters and weight loss regainers show increased cue reactivity. The cue reactivity will be extinguished during extinction training.

Tinnitus, or the ringing of the ears, is defined as the perception of a continuous sound, in the absence of a corresponding acoustic stimulus in the external environment. It is estimated that in Europe over 70 million people experience tinnitus and that for 7 million it creates a chronic incapacitating condition, tenaciously haunting them up to the point where it interferes with every aspect of their daily living. Residing within and confined to the individuals subjective and perceptual experience, tinnitus is not measurable or quantifiable by objective physical recordings, and is furthermore not traceable to disease, injury, or pathology in the brain or elsewhere. Empirical evidence for either the effectiveness of curative tinnitus treatments or for audiological interventions, such as hearing-aids, and sound-generating devices to mask the sound, is lacking. Moreover, the audiometric characteristics of the tinnitus sound (loudness/pitch) hardly predict severity of the condition, or treatment outcomes. Contrary to scientific evidence, the clinical practice of masking/attenuating the tinnitus-sound is still the most widespread tinnitus-treatment approach. Presently I propose the counterintuitive conjecture that it is not the sound itself which is so devastating, but rather the fear-conditioned responses and the associated threat appraisals that maintain severe tinnitus disability. Indeed, empirical evidence is growing for the effectiveness of a cognitive behavioral approach and our recent findings support the importance of addressing tinnitus-related fear and fear-responses in the management of patients with disabling tinnitus. In this project I will experimentally test the idea that initial threat-appraisal and fearful responses predict increased tinnitus suffering. In addition, I will test the idea that exposure to the tinnitus sound is an effective way of decreasing fear of tinnitus and disability in the long term, whereas masking the sound is counterproductive. My research may provide an important impetus for the development of novel tinnitus-treatment approaches. Keywords: Tinnitus, threat-appraisal, fear-conditioning, exposure, masking

Climate change influences our world and health. While concerns about climate change, also known as ‘eco-anxiety’, are normal and may even contribute to eco-friendly behaviour, they also threaten mental health. This project investigates the effectiveness of a novel online positive psychology intervention to tackle adverse effects of eco-anxiety in adolescents. The Best Possible Eco Self intervention, based on envisioning a best possible future in relation to climate change, is expected to promote constructive optimism, well-being and pro-environmental behaviour. This project intends to initiate the development of positive ‘eco’ psychology interventions to enhance resilience in the face of climate change.