Psychiatric, psychological comorbidities of typical and atypical Charles-Bonnet syndrome

Objectives

Charles-Bonnet syndrome (CBS) is conventionally defined by the presence of visual hallucinations in patients suffering from lowered visual acuity without having psychosis or dementia. Actually, it is a syndrome that interests many specialties, especially ophthalmology, geriatrics, neurology and psychiatry. “Atypical CBS” or “CBS plus” was introduced to designate any kind of visual hallucinations that could be considered as a CBS but accompanied by a low level of insight, a possible cognitive decline, other hallucinatory modalities etc. Since all patients suffering from CBS have to be psychiatrically evaluated, psychological and psychiatric implications of their syndrome have to be well understood in order to better manage them. These psychiatric and psychological implications are: the relationship between the CBS and dementia, the psychological reaction of the patients towards their hallucinations and psychiatric comorbidities that could be developed during the course of the syndrome.

Methods

A research via MEDLINE for all the articles published in French or in English between January 1999 and December 2009 was done using the following keywords Charles-Bonnet, psychiatric comorbidities and Charles-Bonnet syndrome, Charles-Bonnet syndrome and dementia, psychological reaction and Charles-Bonnet syndrome.

Results

Although some studies report an association between the CBS and dementia, the majority of these studies do not confirm this association and point towards an atypical initial presentation of the syndrome. The psychological reaction accompanying the visual hallucinations of the typical CBS is variable (mild distress, indifference, pleasure). Patients suffering from a typical CBS conserve a full insight during the course of the syndrome. A positive personal psychiatric history or a concomitant psychiatric disorder changes the clinical presentation of the syndrome.

Discussion

Our research allowed us to define the following diagnostic criteria for the atypical CBS: 1) diminished level or absence of insight towards the visual hallucinations; 2) presence of a mild cognitive decline; 3) presence of an atypical psychological reaction towards the visual hallucinations as in the case of a severe and prolonged stressful reaction; 4) presence of other hallucinatory modalities; 5) presence of a positive personal psychiatric history or a concomitant psychiatric disorder. Each patient suffering from CBS should be initially evaluated psychiatrically and neurologically in order to confirm or to eliminate the presence of the most common causes of visual hallucinations. In the presence of a lowered visual acuity and a conserved cognitive functioning, the typical CBS is diagnosed after eliminating more common disorders. Once this diagnosis is established, patients should be evaluated in order to rule out the presence of an atypical clinical presentation.

Conclusion

Atypical CBS is a syndrome that could be eventually associated with dementia, accompanied with a major depressive disorder or another psychiatric disorder, or with vulnerability towards psychiatric disorders. Patients suffering from atypical CBS should be closely followed psychiatrically and neurologically. Patients suffering from the typical CBS should also benefit from a psychiatric follow-up, due to their multiple psychiatric vulnerability factors and their possible management with psychotropic drugs.