Ms. A, a 56-year-old postmenopausal patient with a 30-year history of paranoid schizophrenia, was admitted to the hospital for an acute exacerbation of her mental disorder. Upon admission, bizarre paranoid delusions and auditory hallucinations were present. A medical history and a physical examination revealed no somatic disorder. Aripiprazole was then initiated at 15 mg/day. Twenty-six hours after her first dose—30 mg—she complained of palpitations. The findings of a physical examination were tachycardia (120 bpm, regular) and arterial hypertension (220/110 mm Hg). Her neurological state was normal. Aripiprazole treatment was interrupted, and Ms. A’s blood pressure returned progressively to its usual range (130/90 mm Hg) over 72 hours without treatment. Aripiprazole was then started again at 15 mg/day. Symptoms (palpitations) and signs (a heart rate of 120 bpm and blood pressure of 220/110 mm Hg) recurred over a few hours. Ms. A was successfully treated with propanolol, and aripiprazole was stopped. A first-generation antipsychotic was introduced, and both somatic and psychiatric outcomes were favorable. Common causes of a hypertensive crisis (an interruption of antihypertensive medication, endocrine and renal diseases) were ruled out.