Despite the possible benefits of dopaminergic agonists and cholinesterase inhibitors for behavioral symptoms associated with dementia, adverse events (orthostatic hypotension, hallucinations, and impulse control disorders for dopaminergic agonists; nausea, vomiting, diarrhea, and insomnia for cholinesterase inhibitors) and withdrawal symptoms with abrupt discontinuation should be discussed with patients and caregivers. This evidence concerns the gene BCHE and insomnia.