Can Self-Reported Seasonality Predict Prospectively Assessed Seasonal Changes of Self-Reported Mood, Food Cravings, Body Weight, Insomnia, and Physical Activity?

Controversy about seasonal affective disorder lies in the poor match between its definition and the available screening methods, as well as little knowledge about the predictive value of specific seasonal symptoms assessed by those methods. We examined whether the overall score as well as sub-domains of the seasonal pattern assessment questionnaire can predict seasonal changes in mood, sleep, appetite, weight, and physical activity in a one-year prospective study. In a sample of 336 Icelandic residents, we administered an online questionnaire once in each season, including the seasonal pattern assessment questionnaire, the depression, anxiety, and stress scale, the Questionnaire on Cravings for Sweet or Rich Foods, the Bergen Insomnia scale, the International Physical Activity Questionnaire, and surveyed body height and weight. We compared participants with at least moderate seasonal changes to a control group of participants without seasonal changes. Only food cravings and physical activity showed seasonal fluctuations. In none of the domains were the seasonal fluctuations predictable by summer-time self-reported seasonal symptoms, neither in terms of general seasonal changes nor in the specific domain. While the overall low rate of seasonal changes limits conclusions, this study adds to the literature that raises doubts about the concept of the predictability of seasonal changes by self-reports.