ACADIA Pharmaceuticals Inc. is a biopharmaceutical company. The Company is focused on the development and commercialization of medicines for central nervous system (CNS) disorders. Its lead drug candidate, NUPLAZID (pimavanserin), is used for the treatment of hallucinations and delusions associated with Parkinson's disease psychosis (PD Psychosis). NUPLAZID is a selective serotonin inverse agonist (SSIA), preferentially targeting 5-HT2A receptors. The Company is conducting a Phase II trial, referred to as the SERENE Study, designed to examine the efficacy and safety of pimavanserin as a treatment for Alzheimer's disease (AD) Agitation. It is also conducting a Phase III, six-week, randomized, double-blind, placebo-controlled, multi-center, outpatient study, referred to as the ENHANCE-1 study, designed to examine the use of pimavanserin in patients with schizophrenia.