Previous research has found that reduced self-reassurance and heightened verbal ‘self-attacking’ of a sadistic and persecutory nature are both associated with greater subclinical paranoia. Whether these processes are also linked to clinical paranoia remains unclear. To investigate this further, we asked 15 people with persecutory delusions, 15 people with depression and 19 non-psychiatric controls to complete several self-report questionnaires assessing their forms and functions of self-attacking. We found that people with persecutory delusions engaged in more self-attacking of a hateful nature and less self-reassurance than non-psychiatric controls, but not people with depression. Participants with persecutory delusions were also less likely than both healthy and depressed participants to report criticising themselves for self-corrective reasons. Hateful self-attacking, reduced self-reassurance and reduced self-corrective self-criticism may be involved in the development or maintenance of persecutory delusions. Limitations, clinical implications and directions for future research are discussed.