RecruitingPhase 2Drug trialPimavanserin for Rigid-compulsive Symptoms in Autism Spectrum DisorderThis Phase 2 study examines the safety, tolerability, and preliminary efficacy of pimavanserin in individuals with Autism Spectrum Disorder. Male or female participants aged 12 to 40 years of age will be randomized to receive single doses of either placebo or pimavanserin in this randomized, placebo-controlled, cross-over designed study, followed by open label extension.