Hormones such as leptin and visfatin regulate appetite and the metabolic state, and consequently affective states. There are links between these hormones and inflammatory markers, which may play a major and possibly causal role in affective disorders. At both ends of the weight spectrum and in conditions like the metabolic syndrome, risk for affective dysregulation and/or depression is elevated. This is often accompanied by motivational anhedonia, i.e. the devaluation of rewards that require greater effort to obtain, avolition and rumination. Physical activity can help to remediate such abnormalities, but the underlying mechanisms remain to be clarified.
In this waiting-list control group study with regular follow-up assessments, a digitally aided 8-week behavioral intervention to promote light daily physical exercise will be delivered via a videobased smartphone application. The study will be conducted in two existing cohorts: help-seeking young individuals (15-35 years old) with at least one risk factor for bipolar disorder (BD) or with depressive symptoms, and middle-aged adults at high risk for diabetes (defined as impaired fasting glucose and/or glucose tolerance). The assessments will include measurement of appetite-regulating hormones, metabolic and inflammatory markers as well as affective symptoms through self-report questionnaires and expert interviews. Furthermore, motivational anhedonia, avolition and rumination will be assessed with ecological monetary assessment (EMA) and a web-based experimental psychology paradigm.
At baseline, we expect positive associations between peripheral hormones signaling an excess of energy stores (e.g., high leptin) and proinflammatory cytokines with markers of depressed mood, such as increased anhedonia, avolition, and rumination, altered circadian rhythm and decreased daily physical activity. We hypothesize that the digitally aided exercise intervention will lead to a decrease of these hormones and pro-inflammatory cytokines at follow-up. Moreover, we expect a decrease of anhedonia, avolition and rumination as well as a normalization of circadian rhythm after the exercise intervention.
- Fürtjes S, Seidel M, King JA, Biemann R, Roessner V, Ehrlich S. Rumination in anorexia nervosa: Cognitive-affective and neuroendocrinological aspects. Behav Res Ther. 2018;111:92–8. doi:10.1016/j.brat.2018.10.001.
- Jaganathan R, Ravindran R, Dhanasekaran S. Emerging Role of Adipocytokines in Type 2 Diabetes as Mediators of Insulin Resistance and Cardiovascular Disease. Can J Diabetes. 2018;42:446-456.e1. doi:10.1016/j.jcjd.2017.10.040.
- Pil-Byung C, Shin-Hwan Y, Il-Gyu K, Gwang-Suk H, Jae-Hyun Y, Han-Joon L, et al. Effects of exercise program on appetite-regulating hormones, inflammatory mediators, lipid profiles, and body composition in healthy men. J Sports Med Phys Fitness. 2011;51:654–63.
Skills/qualities required especially for this project:
- Interest in working with individuals at-risk for diabetes or bipolar disorder and in acquiring knowledge about appetite-regulation, endocrinology, inflammation, and experimental psychology in an interdisciplinary research effort.