Dementia With Lewy Bodies, Visual Hallucinations, and Medications

To the Editor: In their recent study, Clive G. Ballard, M.R.C. Psych., M.D., et al. (1) “confirm” high frequencies of visual hallucinations and delusions in dementia with Lewy bodies and also conclude that visual hallucinations are significantly more persistent in this disorder than in Alzheimer’s disease. Although extensive clinical evaluations were performed before death, the authors do not report the medication status of their patients. The impact of dopaminergic drugs on the mental state of demented parkinsonian patients should not be ignored. It is interesting that 66% of the patients with dementia with Lewy bodies in this study had visual hallucinations. A prior meta-analysis of dementia with Lewy bodies reports noted that 68% of the patients with dementia with Lewy bodies receiving dopaminergic drugs had visual hallucinations, but only about half that rate was found in medication-free patients (2). Dr. Ballard et al. may be prematurely attributing visual hallucinations to the pathological process of dementia with Lewy bodies per se rather than to an epiphenomenon, i.e., medication status. A review of their patients’ medications could shed light on this question.