Can Deaf People with Schizophrenia Have Auditory Hallucinations?

Schizophrenia is a psychotic disorder, with a wide range of symptoms, such as hallucinations, delusions and difficulty with concentration to name a few. Within hallucinations, the most common type is auditory hallucinations, with up to 75% of patients reporting “hearing voices”. With this being such a common (core) symptom for people living with schizophrenia, what is the experience like for those who cannot hear? Are there differing rates of these types of hallucinations, or are they under recognised in deaf people?

The prevalence of schizophrenia within the deaf community is roughly the same as that for the general population. Around half of deaf people with a schizophrenia diagnosis report hearing voices in the absence of any external stimuli – which is almost as high as rates for auditory hallucinations found in hearing people with schizophrenia. Interestingly, deaf people with schizophrenia have higher rates of visual and tactile hallucinations (roughly 50%), in comparison to hearing people (15% and 5%), despite these types of hallucination generally being less common in schizophrenia. Both these types of hallucination can often occur alongside “voices” in deaf people with schizophrenia, which suggests there is a link between the different types of hallucination.

There is variation in the content of auditory hallucinations within the deaf community, depending on whether an individual has been deaf from birth, or developed hearing loss later in life. For those who have been deaf from birth, they may experience visual or physical hallucinations such as moving lips, sign language movements or facial expressions. This can be misinterpreted by clinicians who can hear as the individual “hearing voices”, due to lack of understanding. For individuals who developed hearing loss later in life, they may experience “true” auditory hallucinations, and interestingly the frequency of these hallucinations increase as the severity of their hearing loss increases – in one study they found in the previous month 16% experienced “hearing voices”, however in those with the most severe hearing impairments, the rate was 24%.

There is not a huge amount of research available on this subject, however it is clear that there is a lack of understanding amongst clinicians regarding the experience and content of hallucinations in schizophrenia patients who are also part of the deaf community. A huge amount of the language and terminology used is focused on hearing people with schizophrenia, and within psychiatry we need to be aware of the different experience of hallucinations for those with hearing loss. Also, given the statistics, it is important not to overlook schizophrenia as a diagnosis, purely based upon the absence of auditory hallucinations, and this is applicable to both hearing and deaf people.

If you would like to read more about this topic, the articles used are listed below. The Perceptual Characteristics of Voice-Hallucinations in Deaf People: Insights into the Nature of Subvocal Thought and Sensory Feedback Loops – J. Atkinson

Prelingually profoundly deaf schizophrenic patients who hear voices: a phenomenological analysis. – M. du Feu, PJ McKenna

Hallucinatory modalities in prelingually deaf schizophrenic patients: a retrospective analysis of 67 cases – K. Schonauer, D. Achtergarde, U. Gotthardt, HW. Folkerts

The Impact of Deafness on Hallucinations and Delusions – Nicola Davies (psychiatryadvisor.com)