Perfectionism has been associated to Perseverative Negative Thinking [PNT]. Both are transdiagnostic processes. PNT (in the form of worry and rumination) is a prime candidate when investigating negative components of perfectionism (Macedo et al., 2013).

To investigate if PNT mediates the relationship between perfectionism and negative affect [NA].

344 university students (68.4% girls) were evaluated using Portuguese validated versions of the Perseverative Thinking Questionnaire (two subscales:’Repetitive Thought’ [RT] and’Cognitive Interference and Unproductiveness’ [CIU]), Multidimensional Perfectionism Scale, Profile of Mood States and Perceived Stress Scale, with an additional item to evaluate perceived social support [PSS]. Only variables significantly correlated with the outcomes [NA] were entered in the hierarchic multiple regression models. Mediation analyses using Preacher and Hayes bootstrapping methodology were performed.

Perceived Stress [PS] ((=.245), PSS ((=-.257), Self-Oriented Perfectionism [SOP] ((=-.126), Self-Prescribed Perfectionism [SPP] ((=.122; p=.011), Concern over Mistakes [CM] ((=.102), Doubts about Actions [DA] ((=.115) and CIU ((=.110) were significant predictors (all p<.05) of NA. Controlling for PS and PSS, the perfectionism variables still predict depression, accounting for a significant increment of 16.7% (p<.01). The CIU, introduced in the model after the Perfectionism variables, significantly increments the NA variance in 1.6% (p<.01). CIU was a total mediator in the relationship between SOP and NA (IC95% .025-.229) and a partial mediator in the relationship between SPP (.176-.456), CM (.142-.855), DA (.143-.863) and NA.

PNT potentiates the relationship between negative perfectionism and NA. Positive perfectionism is associated with NA, only in the presence of PNT.