Chronotype and personality factors of predisposition to seasonal affective disorder

摘要

The study aimed to recognize the personality factors of a predisposition to seasonal mood fluctuations in a nonclinical sample. A group of 101 subjects (57 women, 44 men; mean age 26.4 ±6.5 years) completed a battery of tests comprising a Seasonal Pattern Assessment Questionnaire (SPAQ), Chronotype Questionnaire (ChQ), a NEO-Five Factor Inventory and a Coping Inventory for Stressful Situations (CISS). A smaller sample (n = 44) completed a Winter Blues Scale (WBS). Women scored significantly higher than men in seasonality (p =0.014), neuroticism (p = 0.049), agreeableness (p =0.010), and avoidance-oriehted coping style (p =0.041). Subjects with seasonal affective disorder (SAD) (n=41) or sub-SAD (n = 33), as diagnosed with SPAQ, exhibited higher levels of neuroticism (p = 0.017) and openness (p = 0.016) in comparison to non-SAD individuals. The latter declared a less frequent avoidance coping style. Both measures of seasonality, i.e. the SPAQ Global Seasonality Score and WBS, correlated significantly (r=0.28 and 0.44, respectively) with the subjective amplitude of the circadian rhythm, as described with the "distinctness" scale of ChQ. Female gender, neuroticism and openness were confirmed as factors linked to seasonal mood variability. Additionally, the study revealed an association between susceptibility to mild winter depression and an avoidance-oriented coping style. The avoidance coping style was correlated positively with all the aspects of seasonality described by SPAQ (correlation coefficients from 0.21 to 0.34). Both sub-types of avoidance-oriented style, i.e. distraction and social diversion, were associated with marked subjective seasonal changes in sleep length, mood and the energy level. While the subjective amplitude of circadian rhythm proved to be connected with seasonality, the subjective acrophase of the rhythm (morningness-eveningness preference) did not. It may be hypothesized that sensitivity to natural environmental conditions/synchronizers is a separate individual trait shaping the subject's proneness to energy and mood changes both in diurnal and year scale, i.e. circadian and seasonal mood variations.