[A case of Usher's syndrome associated with psychotic symptoms: diagnosis and follow-up in a psychiatric unit].

INTRODUCTION: Usher's syndrome is a heterogeneous autosomal recessive disorder characterised by dual sensory impairment: profound congenital hearing impairment and progressive visual loss due to retinitis pigmentosa, sometimes associated with vestibular dysfunction. Some patients develop a psychotic illness, the etiology of which is still debated. Diagnosis may be difficult, and there are only a few reports in the psychiatric literature.

CASE REPORT: The present case reports a 57-year-old man, double diagnosed with sensory impairment and psychosis. The severity of his psychosis required several hospitalisations in a psychiatric in-unit, even under third party decision or compulsory hospitalisation, for acute states with disruptive behaviour, aggressiveness against his mother, persecutory delusion and auditory hallucinations, self-talking, major anxiety, and depressive affects, without dissociation. Deafness had been diagnosed when he was six years old; he was able to attend school and learn to read and speak, using hearing aids, and was able to hold a job for three months. Severe psychotic symptoms appeared when he was 18 years old and contributed in confirming the diagnosis. Progressive loss of vision until blindness began later, between the age of 40 to 50. No specific abnormal results were revealed during the neuroradiological check-up. Treatment consisted in antipsychotics, notably depot, first in a mental health care in-unit and subsequently in an out-patient unit: although he denied psychotic symptoms, he became compliant with medication and could go on with treatment, associated with multidisciplinary interventions at home, in order to improve his quality of life.

DISCUSSION: Usher's syndrome is the most frequent cause of combined deafness and blindness in adults (three and five individuals per 100,000), but difficulties in communication need to increase clinical awareness of this disorder, especially for psychiatrists. Three subtypes are recognized by the International Usher Syndrome Consortium: Type 1 is characterised by profound congenital deafness, retinal degeneration beginning in childhood, and progressive vestibular dysfunction; Type 2 is characterised by moderate to severe hearing impairment, later onset of retinal degeneration, and normal vestibular function; Type 3 is characterised by progressive hearing loss and variable age of onset of retinal degeneration. Although nearly 23% may have psychotic symptoms, the aetiology remains unclear: sensory deprivation associated with environmental stress, organic changes such as cerebral abnormalities, genetic link (two genetic loci for both Usher's syndrome and psychotic illness are very close). Treatment of psychiatric symptoms is based on antipsychotics, well tolerated by the patients, who improve change of behaviour and communication abilities. Genetic counselling may be useful for parents.

CONCLUSION: Access to mental health services is particularly difficult for deaf and deaf-blind people, and difficulties in communication are a challenge for patients and for caregivers too. Antipsychotic medications are helpful for associated psychotic symptoms. Potential link between Usher syndrome and psychosis is still unclear and needs further studies.