There were unexpected findings as well. First, an association between the tendency not to react to upsetting feelings and ASPD traits and aggression could be predicted, while no significant relations appeared. One possible explanation is that the Non React scale of the FFMQ mostly captures the tendency to abstain from reacting emotionally (e.g., getting upset for what one is feeling, or being overwhelmed by disturbing emotions) rather than measuring physical acting-outs which are likely to characterize people with ASPD. Indeed, ASPD clients are prone to avoid upsetting feelings rather than thinking about and being overwhelmed by them [10], [19]. Another possible explanation is that the relatively low internal consistency of the Non React scale could have deflated correlation coefficients. Future studies need to use different measures using interviews to assess mentalizing or metacognition — such as for example the Mastery scale of the Metacognition Assessment Scale [45], which taps the ability to use awareness of mental states for purposeful problem solving. We would expect that persons with more abilities to purposefully use knowledge of mental states, both of the self and the others, for interpersonal problem solving could be more able to regulate interpersonal problems and conflicts with strategies other than aggression.