Feeding and extinguishing the flame: the nature, provocation, and treatment of transdiagnostic hostility

Hostility is a character trait. People with this character trait often feel angry, have hostile thoughts and can behave aggressively. Increased hostility is common among mental healthcare clients. The current thesis was written to gain a better understanding of the nature of hostility and how it is generated and can be reduced. There is actually no consensus on the definition of hostility. We are not sure how best to provoke hostility, and the treatment options leave room for improvement. The results show the following. First, hostility consists of several aspects, namely experiencing angry feelings and hostile thoughts and engaging in aggressive behaviour. Secondly, social exclusion and an insult arouse similar levels of hostility, but there are individual differences in the extent to which someone is susceptible to these. Thirdly, when we use mental images (instead of words) during psychotherapy it increases the efficacy. Finally, in this study, an online intervention was developed that proved effective in reducing hostility.