The perception of stress does not automatically lead to prolonged activation. The cognitive representations of stressors need to be prolonged in order to extend their physiological concomitants (Brosschot, Gerin, & Trayer, 2006). It is shown that elevated levels of repetitive negative thinking appear to be causally involved in the maintenance of emotional problems (Ehring & Watkins, 2008).

To analyze the associations between Perceived Stress (PS), Perseverative NegativeThinking (PNT) and Sleep difficulties.

549 students from two Portuguese Universities filled in the Portuguese version of Perceived Stress Scale (Cohen et al., 1983; Amaral et al., 2014), PerseverativeThinking Questionnaire (Ehring et al., 2011; Chaves et al., 2013), and three questions were used to access sleep difficulties (initiating sleep, sleepmaintenance, and early morning awakening).

In the present sample the prevalence on difficulty initiating sleep was 29,8%, of maintaining sleep was 27,9% and of early morning awakening was 30,9%. The strongest correlations were observed between PS and PNT (from r=.338 to r=.520; p<.01), being slighthigher to Cognitive Interference and Unproductiveness dimension. The correlations between PS and difficulties in initiating and maintaining sleep were from r=.314 to r=.366 (p<.01). Considering PNT and Sleep associations, strongest correlations were observed in relation to difficulties of initiating sleep (from r=.206 to r=.222; p<.01) and weaker in relation to difficulties in maintaining sleep (from r=.125 to r=.198;p<.01).

The PS was strongly associated with PNT and both of these variables were associated with sleep difficulties (particularly initiating and maintaining sleep).