Main author: Yvonne Höller
Institution or Company: Faculty of Psychology, University of Akureyri, Iceland
Co-Authors, Institution or Company:
Sara Teresa Jónsdóttir, Faculty of Psychology, University of Akureyri, Iceland. Anna Hjálmveig Hannesdóttir, Faculty of Psychology, University of Akureyri, Iceland. Ragnar Pétur Ólafsson, Faculty of Psychology, University of Iceland, Iceland.
Introduction: Seasonality is operationalized as seasonal variation in mood, appetite, weight, sleep, energy, and socializing. No EEG studies have been conducted on induced sad mood in relation to seasonality, and no studies so far have controlled for age.
Methods: We recorded EEG in 114 participants during rest and during induced low mood in summer. Participants were divided into groups based on seasonality scores and age. We calculated bandpower in the delta, theta, alpha, and beta range.
Results: Participants with high seasonality showed larger changes in EEG power, specifically the alpha frequency range, than participants with low seasonality (p=.027). Furthermore, seasonality interacted with age (p<.001), with higher broad-band activity in high-seasonality compared to low-seasonality individuals over 50 years of age, but the opposite pattern, except for alpha frequency range, in individuals up to 50 years.
Conclusions: Effects of sad mood induction on brain activity are related to seasonality but change with age. We suggest that age needs to be considered in future EEG studies in seasonality and seasonal affective disorder, and that EEG responsivity to sad mood induction should be further investigated as a potential predicting biomarker for seasonal affective disorder in longitudinal studies.