Background: Cognitive models of mental contamination (i.e. feelings of internal dirtiness without contact with a contaminant) propose that these feelings arise when individuals misappraise a violation. However, an operational definition of 'violation' and identification of specific violation misappraisals is limited.

Aims: This study's aim was to elaborate on cognitive models using qualitative data from those with lived experience to fill these gaps.

Method: Twenty participants with a diagnosis of obsessive-compulsive disorder and/or a trauma history took part in a semi-structured interview about violation. Grounded theory was used to analyse interview transcripts.

Discussion: Three categories emerged, each with several themes - qualities of violation, violation-related appraisals, and violation-related behaviours. Different violation-related appraisals were associated with different emotions and urges. Specific self-focused appraisal sub-themes (i.e. permanence of consequences; self-worth; responsibility, self-blame and regret) were most closely related to emotions tied to mental contamination. These findings support and expand upon existing cognitive models of mental contamination, identifying key violation-related appraisals and differentiating between mental contamination-related appraisals and those related to other emotional sequelae. Future quantitative and experimental research can evaluate the potential of these appraisals as intervention targets.