Affective style and eating disorders: a field study.

Eating disorders (ED) are a heterogeneous group of problems related to restraint and/or overeating. It is proposed that individual differences in affective reactivity and moods (affective style) might be related to these behaviours. Variations in affective style are expressed by differing levels of sensitivity to the motivation systems of approach and avoidance. The present study tested whether a relation exists between ED and variations in the sensitivity of motivational systems as well as mood dispositions. A total of 2020 undergraduate students completed the Eating Disorder Diagnostic Scale (EDDS), the Behavioural Inhibition System and Behavioural Activation System Scales (BIS/BAS), and the Positive and Negative Affect Schedule (PANAS). The results showed a significant within- subject interaction of Alimentary group x Motivation (F=4.056; p<0.007). It was also observed that the Overeating group had lower levels of motivation asymmetry than the Normal (p<0.01) and Restrictive (p<0.005) groups and marginally lower levels than the Purgative group (p<0.07). The study results suggest mainly that the avoidance/inhibition motivational system is related to eating problems connected with overeating, including chronic alimentary restraint (chronic dieters). The theoretical and clinical implications of these findings are discussed.

Sleep pattern and daytime differences in the electromyographic activity and peripheral temperature.

For a long time, it has been said that most individuals sleep an average of 8 h. However, there are subjects that usually sleep less than 6 h (the ones placed under the label of short sleep pattern, SSP) and subjects that sleep more than 8 h (those classified by the long sleep pattern, LSP). Starting from this division, several studies have been carried out in order to establish possible differences in terms of psychological and physiological variables. This study is aimed at assessing the differences that might occur in electromyographic activity and temperature in long, medium and short sleep pattern subjects at two moments in the day. From a 300-subject sample, 17 long sleep pattern, nine medium sleep pattern and eight short sleep pattern subjects were selected. The physiological variables were assessed during a constant stimulation task in the morning (between 09.00 and 10.00 h) and in the evening (between 19.00 and 20.00 h). The inter-group analysis showed that the long sleep pattern and the short sleep pattern subjects differed in terms of electromyographic activity in the morning. This same analysis indicated that only long sleep pattern subjects showed changes in electromyographic activity over two measurements taken in the same day. The results point out that long sleep pattern subjects show more sensitivity towards changes, and that sensitivity is expressed in a different manner, depending on the time of the day.