This study is looking at Lewy Body Dementia Psychosis, a condition where people with a type of dementia called Lewy body dementia experience hallucinations or false beliefs. Lewy body dementia is a brain disorder that affects thinking, movement, and behavior, and when it includes seeing or hearing things that are not there or having unusual beliefs, it is called Lewy Body Dementia Psychosis. The study will test a medication called ACP-204 in capsule form, which will be given by mouth. Some participants will receive placebo instead of the actual medication. The purpose of this study is to find out if ACP-204 works to reduce the symptoms of hallucinations and false beliefs in people with this condition, and to compare two different doses of the medication to see which one works better.

During the study, participants will take either ACP-204 at a dose of 30 milligrams daily, ACP-204 at a dose of 60 milligrams daily, or placebo for a period of six weeks. The main goal is to see if there is an improvement in symptoms related to hallucinations and false beliefs by measuring changes using a special rating scale designed for people with Lewy Body Dementia Psychosis. This scale looks at specific symptoms like seeing things that are not really there or having beliefs that do not match reality.

The study is designed to be double-blind, which means that neither the participants nor the doctors will know who is receiving the actual medication and who is receiving placebo during the treatment period. The treatment will last for six weeks, and doctors will check how well the medication works by comparing the symptoms at the beginning of the study to the symptoms at the end of the six-week period. This research is intended to help understand whether ACP-204 can be a helpful treatment option for adults living with Lewy Body Dementia Psychosis.