Methods: Participants were recruited with the assistance of local mental health agencies. Across two sessions, diagnostic information was collected and cognitive and SC measures were administered in sign language or spoken English. A qualitative questionnaire was also administered, which asked participants about their experience of visual and voice hallucinations. Grounded theory techniques were employed to produce categories for additional analysis, such as “voices are mean/friendly,” “voices talk to each other/to me,” or “voices feel like they are coming from inside/outside of my head.” We also documented the number of voices as well as the quality of voices (loud/soft, male/female).
Results: The primary finding is that deaf and hearing subjects experienced the phenomenon of voice (and visual) hallucinations in a similar fashion. The volume of voices, the number of voices, their gender, and whether or not voices were argumentative manifested at similar rates across the groups. Some differences in thematic content were evident. For example, deaf subjects were more likely than hearing subjects to incorporate somatic experiences in their descriptions (e.g., “I saw a racoon outside of my window and his spirit jumped inside of me;” “I touched a bus and a spirit went inside of me;” “Someone put a gold bar in my leg”). Notably, voices were often related to somatic content (e.g., “I started hearing voices after [the animal spirit] entered my body”). The mention of color was also more evident among deaf subjects (e.g., “Blue means God wants me to quit smoking”) as were references to the right and left side of the body (e.g., a devil/angel on the right/left shoulder). For all subjects, themes were correlated to results on measures of emotion identification, cognitive ability, history of trauma (physical or sexual), and symptom severity.
Conclusions and implications: The results illuminate the need for more research about the experience of psychosis among deaf people—from phenomenological studies to functional brain mapping investigations. Fluently signing mental health professionals, preferably people who are deaf themselves, are in the best position to deliver mental health services because of their understanding of deaf culture and American Sign Language. Future research should consider how qualitative aspects of hallucinations and delusions may influence illness severity such that meaningful interventions can be developed for the population.