Pimavanserin for Insomnia in Veterans With PTSD

This study is testing pimavanserin, a medication already used for Parkinson's disease psychosis, to see if it can help veterans with PTSD who also have chronic insomnia (severe ongoing sleep problems). **You may be eligible if...** - You are a veteran aged 18 to 64 - You have been diagnosed with chronic insomnia disorder — trouble falling asleep, staying asleep, or waking too early, at least 3 nights a week for at least 3 months - Your insomnia is causing daytime problems - Your insomnia severity score is 15 or higher (moderate to severe insomnia) - You have clinically confirmed PTSD **You may NOT be eligible if...** - You have certain heart conditions or take certain medications that affect heart rhythm - You have a current diagnosis that makes the study drug unsafe for you - You are pregnant or breastfeeding Talk to your doctor to see if this trial is right for you.