The tangled roots of inner speech, voices and delusions.

The role of inner speech in the experience of auditory verbal hallucinations (AVH) and delusions remains unclear. This exploratory study tested for differences in inner speech (assessed via self-report questionnaire) between 89 participants with psychosis and 37 non-clinical controls. We also tested for associations of inner speech with, i) state/trait AVH, ii) AVH-severity; iii) patients' relations with their voices, and; iv) delusion-severity. Persons with psychosis had greater levels of dialogic inner speech, other people in inner speech, and evaluative/motivational inner speech than non-clinical controls. Those with state, but not trait AVH had greater levels of dialogic and evaluative/motivational inner speech than non-clinical controls. After controlling for delusions, there was a positive relation between AVH-severity and both evaluative/motivational inner speech and other people in inner speech. Participants with greater levels of dialogic inner speech reported better relations both with and between their voices. There was no association between delusion-severity and inner speech. These results highlight the importance of better understanding relations between inner speech and AVH, provide avenues for future research, and underscore the need for research into the interrelatedness of inner speech, voices and delusions, and the complexities involved in disentangling these experiences.