Dexmedetomidine in the Treatment of Agitation Associated With Schizophrenia and Bipolar Disorder (SERENITY III)

A patient may enroll in only one part of the study; either Part 1 or Part 2. Inclusion Criteria: * Male and female patients between the ages of 18 to 75 years, inclusive * Patients who can read, understand and provide written informed consent. * Patients who have met Diagnostic and Statistical Manual5/5-Text Revision criteria for bipolar I or bipolar II disorder, schizophrenia, schizoaffective or schizophreniform disorder. * Patients who, in the opinion of the Principal Investigator, are in good general health before study participation based on a detailed medical history, a physical examination, a 12-lead ECG, a blood chemistry profile, hematology, and urinalysis. * Participants who agree to use a medically acceptable and effective birth control method Part 1 only * Patients who are judged to be clinically agitated at Screening and Baseline with a total score of ≥ 14 on the 5 items (poor impulse control, tension, hostility, uncooperativeness, and excitement) comprising the PEC. * Patients with a score of ≥4 on at least 1 of the 5 items on the PEC at Baseline. Part 2 only * Patients have had at least three clinical presentations of agitation requiring an intervention (e.g., receipt of as needed \[PRN\] medication for the episode, clinic visit, emergency room visit, emergency medical services intervention, law enforcement intervention) in the past three months prior to Screening * Patients who are receiving stable psychotropic treatment for 30 days prior to Screening for…