Positive and negative affect during the school day and its relationship to morningness–eveningness

We carried out a field study in adolescents in a German school to assess their actual affective state during the first and last lesson of a school day. Also, we wanted to assess if chronotype or sleep duration has an influence on affect. One hundred and nine girls and 110 boys participated in the study (mean age: 14.47). The composite scale of morningness (CSM) was used to assess morningness–eveningness and the positive and negative affect schedule (PANAS) was used for affect measurement. Sleep habits were assessed as both, habitual and actual sleep–wake rhythm. Positive affect (PA) was higher in the sixth lesson compared to the first one, but negative affect (NA) was not. CSM scores were positively correlated with PA during the first and last lesson. The correlation coefficient was higher in the first lesson of the day. NA was unrelated to CSM scores. Pupils with a shorter actual sleep duration had a higher NA. Habitual sleep duration was unrelated to affect measures. The results showed no synchrony effe...