A 51-year-old female patient with bipolar disorder 1, characterized mainly by manic phases with psychotic symptoms, comes to our attention after a long history of illness. At the initial evaluation, the patient is being treated with lithium salts, sodium valproate and olanzapine. The psycho-affective picture is stable but the patient has grade 2 obesity and significant dyslipidemia. Therapy with olanzapine is gradually reduced until it is stopped and, given the reappearance of expansive symptoms, it is replaced with perphenazine (initially 8 mg/day, increased to 16 mg/day after a week), with resolution of the picture. In the following 10 years, the patient has a good psycho-affective balance with a maintenance therapy based on mood stabilizers and low-dose perphenazine. Furthermore, the patient manages to maintain body weight and lipid profile within normal limits.