The Charles Bonnet Syndrome: a Systematic Review of Diagnostic Criteria.

PURPOSE: To perform a systematic review of diagnostic criteria for the Charles Bonnet syndrome (CBS).

RECENT FINDINGS: Across 33 studies that specified diagnostic criteria for CBS, hallucinations and vision loss were a common requirement, but there was considerable heterogeneity regarding hallucination properties (i.e., formed vs. unformed) and the severity of vision loss. The exclusion of confounding neuropsychiatric disorders was also common, but specific disorders and their method of ascertainment were variable. There is considerable diagnostic heterogeneity for CBS in the literature. These differences have important implications for the results of observational and interventional studies of CBS and highlight the need for unified diagnostic criteria.